THE PUGET LOWLAND EARTHQUAKES OF 1949 AND 1965

REPRODUCTIONS OF SELECTED ARTICLES DESCRIBING DAMAGE

Compiled by GERALD W. THORSEN

WASHINGTON DIVISION OF GEOLOGY AND EARTH RESOURCES INFORMATION CIRCULAR 81

1986

• •~.__.•• WASHINGTONNatural STATE Resources DEPARTMENT OF Brian Boyle - Commissioner ol Public Lands -- Ar1 Stearns • Supervuor

• J I·' •

F ront oove r :

Falling parapets and ornamentation, rooftop water tanks, chimneys, and other heavy objects caused widespread damage during both the 1949 and 1965 events. Such falling debris commonly damaged or destroyed fire escapes, such as the one in the upper left. This Seattle Times photo shows Yesler Way on April 13, 1949. (Photo reproduced by permission of Seattle Times)

Back cover:

A. Earthquake-triggered landslides cut rail lines in both the 1949 and 1965 events. This slide occurred between Olympia and Tumwater. (1965 Daily Olympian photo by Greg Gilbert)

B. "Sand boils" were created by geysers of muddy water escaping from saturated sediments along Capitol Lake. Soil liquefaction, such as occurred here, was a common source of damage in low-lying areas of fill underlain by flood plain, tide flat, or delta deposits. Sidewalk slabs in this 1965 Oivision staff photo provide scale.

C. Suspended fluorescent light fixtures, such as this one in an Olympia school, commonly sustained damage du ring the 1965 quake . Three mail sorters were injured in the newly completed Olympia post office when similar fixtures fell. (Daily Olymp ian photo by Del Ogden) WASHINGTON DIVISION Of GEOLOGY AND EARTH RESOURCES Raymond Lasmanis. State Geologist

THE PUGET LOWLAND EARTHQUAKES OF 1949 AND 1965

REPRODUCTIONS OF SELECTED ARTICLES DESCRIBING DAMAGE

Compiled by GERALD W. THORSEN

WASHINGTON DIVISION OF GEOLOGY AND EARTH RESOURCES INFORMATION CIRCULAR 81

1986

., WASHINGTON STATE DEPARTMENT OF IIW.a Natural Resources Brian Boyle • Commissioner ol Public Lands Ar1 Stearns • Supervtsor This report is for sale by: Publications Washington Department of Natural Resources Division of Geology and Earth Resources Mail Stop PY-12 Olympia, WA 98504

Price $ 2.32 Tax .18 (Washington residents only)

Total $ 2.50

Mail orders must be prepaid; please add $1.00 to each order for postage and handling. Checks must be payable to the Department of Natural Resources.

Printed in the United States of America CONTENTS

Page Introduction •• ...... • • • 1 Ackn<>Nledgments ...... 1 1949 earthquake Lessons in structural safety learned fron the 1949 Northwest Earthquake lnstal lment 1 • ...... 3 lnstal lment 2 • ...... 8 lnstal lment 3 • ...... • 12

Reporting the Northwest Earthquake--Damage to bui I dings • •• • 15 Reporting the Northwest Earthquake--F ran a scientific point of vie.v ...... • • 19 United States Earthquakes, 1949 •••••• •• •••• . . • • 2 5

1965 earthquake The Puget Sound, Washington, Earthquake of Apri I 29, 1965 •• • 35 United States Earthquakes, 1965 •• •• ...... • • 91

Selected references ...... 113

iii

THE PUGET LOWLAND EARTHQUAKES OF 1949 AND 1965

Reproductions of selected articles describing damage

Compiled by Gerald W . Thorsen

INTRODUCTION

Since the Puget Sound region's most damaging recorded earthquake in 1949, the population of the Puget Lowland has more than d>ubled. Thus, the potential for damage and loss of life in future earthquakes has increased dramatically. Many of the reports of damage caused by that earthquake and more recent quakes were in publications of limited circulation, and many are out of print. Relatively few per­ sons living in the area today were here during the 1949 event. This selection of reproduced information about the 1949 and 1965 earthquakes is intended to alert newcomers, as well as to remind the older residents, that the Puget Lowland is •earthquake oount ry • •

To help bring these earthquakes into current perspective, both monetary and population inflation should be considered. Using current U.S ." Department of Commerce 'price inflators", damage from the 1949 and 1965 earthquakes 'M>uld approach $140 million and $40 million (in 1985 dollars), respectively, Human losses are more difficult to project because of the importance of the time at which a quake occurs. For example, Hopper and others (1975), assuming a 7 .5- magnitude event in the southern Puget Lowland during business and school hours, estimate as many as 2,200 deat hs, 8,700 serious injuries, and 23,500 temporarily homeless.

While examining the photographs of damage herein, one should keep in mind a fundamental shortcoming of our knowledge of seismic history: It is too short. The relative recency of settlement of the Pacific Northwest makes it difficult to project what is "normal' . Major earthquakes, like \Olcanic eruptions, may not occur twice in an individual's lifetime. The 1949 quake may not have been repre­ sentative of maximum shaking, duration of shaking, or depth of focus. Indeed, evidence is building that the Pacific Northwest could be subjected to an event of 8+ magnitude similar to the 1964 Alaska earthquake. Nevertheless, these accounts should remind us of some of the kinds of effects we can expect from the next damaging earthquake.

ACKNOWLEDGMENTS

We thank James E. Bihr, president of the International Conference of Building Officials, for permission to reprint the two articles from their 'Building Standards' monthly periodical. Barbara Guptill, managing librarian in the Governmental Research Assistance Library of the Seattle Public Library, provided us with original articles for reproduction here. 2

Linda Johnson, of the Library of Congress, searched the records and confirmed that there had been no copyright renewal for the three articles from 'Western Construction•, a magazine that long ago ceased to be published. Don Duncan, Washington State Library, provided us with the original editions copied herein.

Jean Boucher, librarian for Shannon and Wilson in Seattle, was very helpful in loaning reports from their extensive collection. Gary Lundell, of the University of Washington Archives, made the Alfred Miller collection available for examination and arranged for copying of some of the photographs in this report.

Our special thanks to Connie Manson, I ibrarian for the Division of Geology and Earth Resources, for her untiring effort in tracking oown rare publications and clearing the way for their reprinting. Reproduced from Western Construction, v. 26. no. 2. p. 70-74 (February 1951) 3

1st Installment: Complete Report of a 2-Year Committee Study on- LeSSOnS in Structural Safety Learned From the 1949 Northwest Earthquake

A BOUT NOON, Pacific Stand­ By HARLAN H. EDWARDS Yes, luck- if you want to calJ it that­ ard Time April 13, 1949, radio listeners Chairman, Earthquake Committee was with us that day. Or could one call were startled by excited announcements Seatlle Section, American Society it the "handwriting on the wall ?" of a violent earthquake in western In the comparatively small proportion of Civil Engineen Washington and Oregon. By declara­ of buildings damaged, shocking condi­ tions of disaster which grew in size with tions of building weakness were dis­ each broadcast the impression was given Neither scenic beauty nor natural wealth closed, conditions of inadequacy of de­ that the cities of the area were a would have availed anything had the sign and of almost criminally cheap con­ shambles, though it was far from the shaking continued a little longer, or had struction, duplicates of which exist in t ruth. However, frantic friends, rela­ there been the strong aftershocks that almost every city and state. Exposed to tives and others in distant areas who have characterized most of the severe public gaze were the too-often-unrecog­ jammed communication lines for days earthquakes of recent time. T housands nized results of penny-wise and pound­ in efforts to reach their loved ones could of people who were on the streets at foolish policies which convicted owner. not know that this Pacific Northwest lunch time, that most-feared time for architect and builder alike of neglecting area was the world's luckiest place that the occurrence of an earthquake, could to consider in their structures the effect day. have been buried under tons of parapet on human life of natural seismic forces walls, ornamentation and broken build­ But the Northwest was favored ! which long since should have ceased to ing fronts. Thousands of children could be "acts of God," which have occurred Outstanding in natural beauty and have been filing out of the doors of their for ages and which may be expected to moderate in weather, favored as a play­ schools on their way to lunch or play occur anywhere from time to time just ground of the nation, the Northwest was only to be struck down by a hail of lethal as are heavy winds and floods. unquestionably favored at 11 :56 a. m. masonry, could have been crushed in that April 13 by not only the earthquake their rooms by collapsing buildings, or An on-the-spot account of damage but also by the fact that many of the struck down on their playgrounds by Just before noon on that fateful schools were closed "on vacation." falling walls and chimneys. though fortunate April 13, 1949, I was in a construction shack in Chehalis, Washington, checking over plans for a building being erected. Suddenly I How and Why the Seattle Section of ASCE Prepared This Report sensed a vibration and heard a dull ON APRIL 13, 1949, the people of the Society. Beginning on this page is rumble that was foreign to the hustling western Washington and Oregon were the complete report of the Earthquake and hammering of the job. It was more shown that strong earthquakes could Committee of the Seattle Section, A.S. like a heavy truck approaching rapidly occur in their locality. Property damage C.E., the committee being composed of over a rough road. as a result of the quake on that date Harlan H. Edwards, author-chairman; "Something's not right," I thought, totaled more than $15,000,000 and seven Cecil C. Arnold, vice chairman; S. Chas. because vibrations of structures usually lives were Jost. With the quake classified Dearstyne, Elmer E. Gunnette, Homer as VII and VIJI on the Modified Mer­ M. Hadley, Wm. Enkeboll, Thos. Camp­ mean trouble to me. My work is that of calli scale, major damage resulted in bell and Roiger Mittet. a construction supervisor and structural engineer. From years of experience in the low, soft land areas extending from Research was made and studies were Seattle southward to Longview includ­ conducted by the committee into many the West 1 knew that such sounds and ing the cities of Puyallup, Tacoma, aspects of the subject earthquake. These movements were not conducive to the Olympia, Centralia and Chehalis. Minor included the following: health of structures, and particularly the losses were suffered by other communi­ I. Examination of records of this health of the old brick buildings nearby. ties and outlying areas. earthquake and of other earthquakes The thought had scarcely flashed Competent observers in the area agree back as far as recorded. through my mind when the old frame that had the violent phase of this temblor shack weaved and shook, creaking in its continued a few seconds longer, or had 2. Examination of physical earth­ there been aftershocks of any coose­ quake damage in the several areas and every joint to the accompaniment of the quence, the number of people meeting determination of extent and types of unearthly rumble and muffled roar of an sudden death" from buildings collapsing damage caused to structures, utilities, earthquake. My curiositl getting the or masonry facings falling would have equipment and miscellaneous installa­ better of my training to 'stay put" dur­ been appalling. Evidenced by fractures tions. ing an earthquake, I dashed out of the and sometimes-concealed incipient fail­ 3. Collection of records, descriptions door. saw the poles in the alley weave ures, tons of insecure masonry parapet and photographs from all over the crazily and the taut wires swing in jerky walls, heavy cornices, ornamentation shaken area for study and comparison. circles like the jump rope of a pair of and whole faces of weak buildings would 4. Conferences with representatives of kids. I heard the rattle and dull roar of have cascaded down upon the streets bodies experienced with enforcement of the brick walls of the garage across the giving few in the noon-hour crowds a measures to prevent earthquake damage, and study of laws and provisions de­ street falling outward upon the cars chance to escape. parked closely in the lot adjacent. I saw Considering the hazards thus made signed to correct present structural in­ evident, and realizing that engineers are adequacies and to protect against such the c loud of dust arise, then settle slowly in duty bound as a public service to damage in new construction. upon the wreckage of cars that a mo­ carefully analyze those conditions and 5. Discussion, sifting and weighinR" ment before were the pride and joy of make impartial corrective recommenda­ of all the information obtained, and many families. I heard the shouts of tions, the Pacific Northwest Conference developing the final conclusions and excited people, then all was still like the of Earthquake Committees of the Amer­ recommendations, as submitted in the lull after a storm. I wondered what was ican Society of Civil Engineers was report. happening to the noonday crowds in formed under the chairmanship of Prof. The complete report of the committee Olympia, Tacoma, Puyallup and Seattle Alfred L. Miller of the University of is being presented by Wester,, Co11s/r11c­ -whether the quake there had con­ Washington. Member committees were tio11 in three installments, beginning with tinued long enough to cast down upon set up by actions of the local sections of this issue. them the tons of brick, terra cotta, glass and stone that are loosely at tached to

70 WESTERN CONSTRUCTION-February, 1951 4

Jar structures visible from there had fared well so far. Only chimneys were A BRIEF OUTLINE of the complete down, but in that respect the damage report prepared by the Earthquake was almost universal; 1,334 were later Committee, Seattle Section, ASCE, counted by the building inspector of that as it will be published in this and small city. Down the street the Meth­ the following two issues of Western odist Church tower had broken, partly Construction is as follows: falling through the roof into the sanctu­ ary and partly, as usual, over the front FIRST INSTALLMENT (this issue}­ entrance stairs. Luckily, this was not a An on-the-spot account of the quake church day. characteristics and damage to vari­ ous types of structures as back­ Public buildings damaged, as usual ground for recommendations to be A block further on, the children of the presented later; o discussion of the Junior High School were all out on the effects of this quake as compared lawn. Their building did not seem dam­ to others. aged but on circling to the rear I saw the high brick chimney above the boiler SECOND INSTALLMENT (Morch room shattered, with a large chunk on issue}-Focts on how new structures the building side loosened ready to fall con be built and old ones strength­ into the school. It was a good thing for the kids that the shake didn't last longer. ened to become earthquake-resist­ Downtown, a similar chimney did fall ant, based on analysis of damage from a building, coming to rest in the by the Northwest quake. tangled debris of the display room of a TH IRD INSTAL LM ENT (April issue) store. To the south of town several buildings -Recommendations for o new a p­ at the State Training School for Boys proa ch to the design of structures in were badly shattered and partly col­ areas subject to eorthquoke haz­ lapsed, reminding me of the wrecked ards; legislation required to achieve schools of Long Beach, California, on the goal of structural safety in the March 10, 1933. At Castle Rock one of Northwest and elsewhere. the High School students was struck down by falling brick from above the entrance as he left the school for lunch, while at Longview, on the alluvial plain MORE THAN 10,000 unreinforced brid chim­ the many buildings that line the streets. neys in the Northw11t required repair ofter Heaven forbid such a disaster I the quake. Many just turned on a mortar joint, Mindful of the destructiveness of the as al this residence in Kelso, but for too many aftershocks, if they came, I dashed to my created hazards by toppling. car parked in front of the job, got it away from the old masonry buildings, been done in many areas, the radio grabbed my camera and started taking broadcasts were increasingly excited, pictures. As usual, the ornate City Hall exaggerated, and not dependable. and Library entrances were blocked by lt soon became evident that the shock fallen masonry. The structures were over the whole area had been of a roll­ racked and broken. From a vantage ing nature which, like the shaking of a point a few blocks up the hill I could sec bowl of jelly, amplified the movement of that the wood frame residences and simi- structures on the earth's surface, par­ ticularly on soft ground. Some damage THIS FISSURE and others extended about was done to buildings on firm, com­ 100 ft. in an old gravel pit near Centralia. pacted gravelly deposits also, but only At many locations, consolidation of alluvium sufficient to indicate that these areas, by vibratory adion of the earthquake freed too, could be shaken strongly, given the water retained in spaces be.,.,een soil par­ right provocation. ticles, causing geysers of mud. Concealed weaknesses come to view Outside Olympia al an old I-story and SUBSIDENCE OF FILL brought this old piling basement wooden elementary school to view through asphalt pavement in O lympia. structure one complete chimney fell In other area,, piles not driven to refusal away from the building and spread its dropped out of ,ight, while 1ome freo1tond­ length over the playground. The top in9 piles rose. three feet of another chimney crashed through the roof and ceiling to the solid of the Columbia River, heavy damage floor beside the blackboard of a class­ had occurred in places. At Centralia, room. No, there were no casualties, for damage similar to that of Chehalis had the children were on vacation. heen suffered, killing one man down­ The School Board had apparently town who was struck by the falling foreseen the need for a better building, upper walls of a 2-story corner building. because across the street was a new By this time I had calmed down suf­ wood-frame-stucco school just ready for ficiently to turn on the radio in the car. occupancy. It showed no damage, for Hearing the reports of disaster broad­ according to qualified observers from cast, T reali;,:ed that I had better start for Cali fornia it was of the earthquake­ home. As T neared the town of Tenino, resistant design closely approaching the north of Centralia, the broadcast told of concept of engineers and architects ex­ its shattered buildings and of streets perienced in areas where earthquakes strewn with wreckage, but as I drove admittedly occur. through, it was "business as usual." In Olympia another school was near­ False Alarm I Although real damage had ing completion. An unreinforced ma-

fNr9ary, 1951 - WESTERN CONSTRUCTION 71 5

harbor a lluvial fill were damaged. One broke and feU through the roof of its adjoining boiler plam and killed a man. Substantiating the severity of the shock which caused all this and other damage in Olympia, a uthenticated accel­ erograph records were obtained on in­ struments of the Coast and Geodetic Survey, located near the State Highway Laboratory on the downtown tideflat fi ll. These records showed that the force exerted by this quake was more than 4 times the force normally used in designs for complete earthquake reinforcement as done in California where earthquake­ resistant design is now standard practice. Damage at Tacoma At Tacoma, too, were occurrences of great interest, both on the lowlands and upon the hard gravel of the high land above the business district. To the west­ ward the new Tacoma Narrows Bridge was under construction. A very heavy cast steel saddle which ultimately was to receive one of the great cables support­ ing the bridge was temporarily resting on wood blocking 3 ft. above the top of the high bridge tower, bolted tight to the tower top plate with four 1-in. vertical rods. During the quake, according to the testi mony of men working on the tower, the top moved at least 6 ft. from its position of rest, then snapped back the same or greater distance the other way, breaking the bolts and th rowing the casting off. It crashed through a work barge on the water 65 ft. to one side and 507 ft. below. On the Tacoma lowlands as in O lym­ pia, high factory chimneys broke off, parapet walls fell, and a 75-ft. high brick wall fractured 15 ft. from the top, moved out 5 in., but didn't collapse. O n hard grou nd high above the business district the stone masonry tower of the 60-year­ TOP-Poorly onchored brick veneer wos knocked off Seattle structure. The obvious lesson here is o ld county courthouse was badly racked that building focings must be designed to resist a reasonable amount of horixo ntal force. by the shocks. It was so fractured in the BOTTOM-A man was killed in downtown Centralia by the falling upper walls of this 2-story uppor por tion t hat coll apse probably corner building. Had such damage occurred during the rush noon-hour, more would hovo died. would have been certain had the earth movement continued, according to testi­ mony of the building inspector and con­ sonry partition showed a very distinct tions were set up by the earthquake sulting structural engineers later on. In crack about 8 ft. long, although green which caused the near-coll apse of this contrast, a local senior building g roup mortar generally concealed this weak­ la ntern as well as typical shear cracks pooh-poohed the danger of collapse and ness from public view. It was interesting and minor movements in other parts of pleaded "don't demolish it-only the to note that the reported cost fo r the the structure. Many of the stones of the cracks need be pointed up. It is a fi ne new, substantially safe elementary school lantern were separated from the adjoin­ example of period architecture and it was $ 10 per sq. ft. of floor a rea while that ing ones, a few had dropped out and would be a shame to tear it down." T hey of the other, uncertain but ornate school others were hanging loose when the gave little thought to the fact that struc­ was approxi mately $15 per sq. ft. quake stopped. tures once cracked and broken remain Other buildings of the capitol group in that state of suspended destruction Capitol buildings sitting ducks were broken, too. F'arapets and cornices until the next quake occurs, then any­ O lympia was close to the epicenter of were down and many characteristic thing could happen. They gave no con­ the earthquake and damage was notice­ diagonal cracks were noted in interior s ideration to the fact that the main ably greater in the larger structures. partitions and walls. It was particularly structure far below was used by the pub­ Buildings of the State Capitol group, evident that the large blocks of stone, lic, or that it contained the county jail typical of many stone-faced masonry wherever they were, had practicall y no which housed many people against their structu res built throughout the country mechanical anchors or ties to each other will, all carrying definite responsibilities withou t regard to seismic shock were o r to the backing, if any existed. They for maintaining protection. (Note: the materially damaged. The 80-ft. diameter were just sitting there like ducks on a dangerous portion of the tower was later stone-faced reinforced concrete dome of pond. It was noted and confirmed later, removed.) the capitol building erected in 1925 and too, that in common with many similar ri sing 231 ft. above the entra nce terrace structures of the same or greater age, Strange things at Puyallup showed little damage but that was not so little mortar existed in many vertical In nearby Puyallup, strange things concerning the sto ne lantern above it. joints and not much more was seen in had happened. Located on natural As might be expected in a building of many of the bed joints. alluvium having the ground water level this type built without a continuous I n O lympia's businessdistrictsubstan­ 2 to 3 ft. below the surface, many of the fra me and having a heavy inverted pen­ tial damage was suffered, too, while two brick buildings (which dated back many dulum forming the dome, large deforma- tall brick chimneys on the tongue of the years) were damaged. Cornices and

72 WESTERN CONSTRUCTION - February, 1951 6

upper walls had collapsed. Low build­ impetus enough to crash to the street. ings bumped against higher ones having With a goodly part of their "earthquake a different rate of motion in the earth­ life" gone, they now remain in their quake, breaking the higher walls as they weakened condition ready to fall upon stopped short in their square dancing. the people on the walks, come the next Brick moved on brick as much as 3 in. quake. Even without the seismic urge. out w;trd at floor c1nd roof levels of some three or more heavy chunks oi masonry large bui ldings, leavi ng the w1tlls pre­ have fallen in downtown streets of Se­ cariouslv nec1r failure. Broken brick attle in recent months, narrowly missing lined the wide crncks tlrnt were left when pedestrians. street faces of stores stopped on their weaving way to the sidewalk below, lack­ Damage on the tide-flat ing the '·pushover" of the usual after­ On the water-s1tturatewest Seattle to But this was not all. Throughout the the lower downtown section. however, town as least 200 chimneys were rotated substantial damage was done. Structures up to -15 deg., generally°in a clockwise built on piles along the waterfront were direc.tion with respect to the building, whipped violently. /\ 50,000-gal. wood but few fell. Geysers of muddy water stave water tank resting on a reinforced rose in many yards to heights as much concrete platform on 20-ft. high concrete as 3 ft., forming circular deposits of columns above the building had suffered black, sandy clay while in some base­ damage to the columns in the 19-16 earth­ ments the surging earth pushed the quake. Presumably adequately repaired floors up, crushing the furnaces and at that time, but still fractured and piping against the joists :ibovc. weakened at the points of greatest stress, Closed to public view and not under in this the succeeding quake it was pre­ jurisdiction of the city building depart­ cipitated to demolition. Its concrete ment and code, the unanchored roof and platform crashed down through the con­ ceiling beams over the stage of the crete roof slab to the floor below break­ Puyallup High School auditorium slid ing refrigeration lines, destroying the off their supporting masonry walls and building's two elevators and putting the crashed down upon the floor below. 7-storv reinforced concrete refrigeration Three students who were there when wareh-ouse out of service for weeks. IN THE CAPITOL DOME ot Olympia, erected the quake started managed to be clear Cables supporting elev1ttors in other in 1925, unanchored keystone dropped out when the $100,000 crash came. buildings jumped out of their sheaves. and column caps broke away. It takes strong mortar, steel and concrete, besides stone, lo "Almost" at Seattle A heavy track-mounted ·ele..:tric trans- make such structures earthquake-resistant. Seattle, fortunately, was on the north­ erly border of the earthquake's strong former moved up and off its supports at rumbling and rubbling and except for a suhstation and landed on the ground buildings on soft ground, it suffered 17 in. aw,Lr. Elsewhere in the area prc- comparatively little from the shakeup. 1900 brick walls were collapsed, frac­ Not that the buildings were resistant to tured or hulged a nd several o ld down­ earthquakes, I hasten to add (for they town hnildings south of J:1mes Street were far from it) but because the shak­ were so dangerously damaged that they ing stopped too soon for damage to de­ were !;Lier condemned and removed. velop much beyond the cracking stage. Structures on hard ground were shaken, Earthquakes are all different but not hard enough to hurt much. In clarifying public thinking on the Masonry partitions were cracked and snhject of seismic action in relation to spalled, plaster fell, terra cotta facings MA NY UNREINFORCED masonry chimneys people and structures, certain facts stand loosened or sheared. On soft ground were fractured and rotated for more than this out. i\n understanding and .1ppreci1ttion especially, many old building fronts and one, which gave way ot the noshing point of them will remove the suhject from l he parapet walls broke their bonds to the above the roof. A competent designer could realm of mvsticism to that of ordinary rest of the structure but did not receive have avoided this weakness. good sense.- I. Earthc1uakes in themselves are gen­ BRI CK VENEER foiled when improperly anchored to poorly braced frame structure. All structures erally not hazardous. They arc danger­ built of unit material must be thoroughly tied tog ether lo move a, a whole. ous fargely because we make the,~ so b_Y building structures that are weak m their resistance to scism ic forces and hence can be easily shaken apart. They usually come without warning, and ordinarily, destruction occurs within a minute. The ,·iolent phase of the April 13 earthquake lasted less than 30 second~. Longer dunt­ tion or strong aftershocks would have transformed that moderate quake into a great disaster. Compared with torna­ does, cvclones or the like against which we no1v design our structures, orclinnry carthquukcs arc mild. 2_ J\"o two quakes c1re a like. They dif­ fer in acceleration, rate and kind of motion, and in direction, duration nnd extent. One cannot know in advance what to expect. Earthquake motion is propagated through and rclfocted by many different strata from the point of origin miles below the earth's surface. Instead of arriving at the surface in

February, 1951-WESTERN CONSTRUCTION 73 7

joining tension areas caused soil move­ ments which pulled apart or broke underground piping or conduit systems. Visible waves traveling over the earth's surface ( often reported but pooh­ poohed or disbelieved by seismologists at the times of other earthquakes) were seen here and in addition left their im­ print on the sands and soils of the soft areas in several locations. On the Ta­ coma lowlands, definite, though slight parallel ridges about 12 ft. apart were left. In a freshly plowed, disked and leveled field near Kent definite waves with crests about 6 in. high and 30 ft. apart resulted, and on a black-topped road in Pierce County, according to the county engineer, troughs were evident afterward extending diagonally across the pavement for ~ mile having a crest­ to-trough height of 2 to 3 in. In Elma, west of Olympia, the originally-lined-up columns under a light grandstand were observed to "walk" or move up and LEFT-Unanchored roof and ceiling beams over the stage of Puyallup high school auditorium slid down during the quake, deforming the alf supporting masonry walls and crashed to floor, causing $ I 00,000 damage. structure. The importance of strong RIGHT-At Castle Rack, a high school student was kill&d as unanchored gable masonry cascaded struts or solid slabs between footings to ta the walk outside th e ontranc&. There could have been more cosualties. assure that the footings will maintain their relative positions in buildings on waves like the ripples on a lake, they ar­ exception noted was along the faults such material (as required by the earth­ rive as a complex variety of motions. affected by this quake where much more quake-resistant code) is obvious. Some impulses amplify others to create violent motion was seen or made evident strong motion; others combine to by the results on land a nd buildings Action like a huge vibrator weaken or nullify the shock. These op­ near-by. Earthquake impulses acted upon posing phenomena can occur in close the water-saturated alluvium (whether proximity or far apart, depending upon A rocking and a rotation natural or man made) and upon a num­ the characteristics of the quake and of Differing from quakes in other areas, ber of high railroad and highway fills the strata through which the impulses this one was reported by many individ­ like a vibrator in concrete, causing set­ pass. In soft ground areas strong motion uals to have a rocking motion; others tlement up to 8 inches in places near and earthquakes seem sometimes amplified reported a horizontal and vertical rota­ under buildings. At one building in by reflection from enclosing formations tional characteristic. As a child moves a Seattle the ground settled and was like waves are from a wharf or a rocky jump rope to make it swing in wide washed from under a footing by escap­ shore, or are built up over shallow areas circles, so the utility poles in many areas ing ground water. At other buildings, like waves are over a reef in high seas. seemed to introduce a vertical rotary particularly back of bulkheads along and 3. After an earthquake it is surprising movement to the wires held taut be­ in waterfront structures, substantial to see how many buildings remain un­ tween them causing the wires to "wrap" settlement occurred, breaking water harmed in the midst of wreckage-build­ with others nearby. T his phenomenon mains and sewers, pulling electric con­ ings that are the counterparts of others seems to be unique with this quake. duit apart as much as a foot, and causing that have been thoroughly wrecked. Motion which induced the rotation of similar damage to other underground However, due to these amplifying and brick chimneys as much as 45 deg. on a structures. Where compaction by vibra­ weakening combinations of earthquake mortar joint close above a building, tion of passing trains or trucks had forces it is folly for one to assume that (usually at a flashing) was particularly occurred in fills, most of the settlement one's building is adequately strong to prevalent in areas having water-satu­ due to this quake occurred outside the resist earthquakes just because it comes rated alluvium soil such as at Puyallup, line of influence of such equipment, to through an earthquake unharmed. Only Harbor Island (Seattle), parts of Cen­ cause cracks and depressed areas to ap­ by careful examination of a building and tralia, and Kelso, near Longview. The pear at the point of change. by a thorough structural analysis of its consolidation of the alluvium by the frame by an engineer or architect skilled vibratory action of the earthquake freed Shocks severe near faults in such computation and de.sign can this water which previously had been re­ Insofar as is presently known, prac­ be determined and the need for strength­ tained in the spaces between the soil tically no permanent horizontal displace­ ening be discovered. particles. The presence of this released ment along a fault line occurred, though water under the pressure of the surface several opened fissures in soft soil were This quake deep underground soil or mat was evidenced by the geysers photographed and several accounts of Seismologists report that this earth­ of water and mud whi<:h spurted from strong motion near a fault were re­ quake originated at a point approxi­ the ground reportedly as high as 3 ft., ported. mately 30 to 40 miles below the earth's which flowed continuously for as long A fault known to exist near Chehalis surface and located somewhere within as 24 hours, and which filled basements is thought to be responsible for the ex­ the triangle defined on the surface by in the Sears Roebuck area of 1st Ave. S. ceptionally heavy damage to old ma­ the towns of Morton, Little Rock and in Seattle with sand. During this tempo­ sonry structures at the Washington Toledo, Washington, southeast of Olym­ rary flotation of the surface areas the State Training School for Boys, where pia. Its intensity and effect at the sur­ horizontal movements of the quake three buildings were so badly shattered face varied decidedly. As water in a pan created compression zones in some that further use or repair was impos­ is strongly agitated and slopped over the areas. In parts of Puyallup they were so sible. edge by moving the pan with a slow, strong that basement floors were lifted rocking motion, or is confined with rela­ like pistons in a pump as much as 16 in. tively little surface effect by sharp, so that furnaces and pipes were crushed quick motions, so the soft ground areas against the joists above and did not Three-part report to be continued next were affected differently at different recede, while stud or post su pports were month and concluded in the April issue. places. Generally speaking, structures on forced through floors to as much as 8 in. For a synopsis of the installments, see box hard ground got off easier. The principal above. These compression areas and ad- on page 71. 74 WESTERN CONSTRUCTION - February, 1951 8 Reproduced from Western Construction, v. 26, no. 3, p. 85-88 (March 1951)

2nd Installment: Lessons in Structural Safety Learned From the 1949 Northwest Earthquake

S TRUCTURES react to By HARLAN H. EDWA RDS the ground, unanchored terra cotta or earthquakes in the same way, whether Chairman, Earthqua ke Cammittee ceramic veneer broke and fell, and stone they be in Seattle, Boston, Los Angeles Seattle Section, American Society work shook apart. Heavy blocks of the or Tokyo. The principal difference is in various materials were cracked at their the severity, duration and character­ of Civil Engineers points of attachment but did not fall istics of the motion and in the type of during this quake. In the year following, construction that is predominant. Since One need only to see the shattered, however, three heavy pieces of terra earthquakes have occurred before, and pitifully weak masonry buildings after cotta fel l on downtown Seattle side- unquestionably will occur again in the an earthquake to recognize how neces­ Pacific Northwest as well as elsewhere, sary good mortar is to a building. With it is well to know ( 1) how stnuctures of mortar that combines strength, work­ the various kinds were damaged on ability, adhesiveness, minimum bleeding, A BRIEF OUTLINE of the complete April 13, 1949, and then (2) how they low expansion and contraction, and im­ re port prepared by the Earthquake can be constructed or strengthened to permeability, the inherent qualities of Committee, Seattle Section, ASCE, resist being damaged. good rnasonry will be realized. as it is being published in W esfern Older and weaker are first A test for mortar Construction is as follows: In all earthquakes the older, weak From exhaustive research at the Bu­ FIRST INSTALLMENT (Feb. issue)­ masonry structures failed first, and reau of Standards in cooperation with An on-the-spot account of the quake many of them completely. This is true industry, a measure of workability and characteristics and damage to vari­ of the quake under discussion in which quality has been developed in the "water ous types of structures as back­ the modern masonry structures as a retentivity test" which is included in group performed splendidly. But where Federal Specification SS-C-18lb. It is ground for recommendations to be typical earthquake-type fractures did based upon the fact that a good mortar presented later; a discussion of the occur and where one or more walls suf­ is one that contains good materials in effects of this quake as compared fered partial destruction it was reempha­ adequate amounts, and in addition will to others. sized that in addition to good workman­ hold the most water within it for hydra­ ship and substantial materials, all struc­ tion of the cement contained. The use SECOND INSTALLMENT (this tures built of unit materials must be of this measure of quality is gradually issue)-Facts on how new structures thoroughly tied together so that they being adopted by the tni.des and codes. can be bui lt and old ones strength­ move or resist movement as a whole, Exterior finish materials such as un­ ened to become earthquake-resist­ and be so braced that no part can move anchored terra cotta, ceramic veneer, ant, based on analysis of damage beyond its limit of elasticity. In other brick, stone, glass, sheet metal panels, by the Northwest quake. words, all parts of the structure must etc., cracked, shattered, spalled or fell have sufficient strength and stiffness or from the twisting and bending of their THIRD INSTALLMENT (April issue) rigidity to transmit the forces acting related buildings. - Recommendations for a new ap­ upon them into other members able to In some cases inadequately attached proach to the design of structures in receive them, without serious damage to brick veneers fell clear of the structures, areas subl'ect to earthquake haz­ finish materials. glass facings shattered and dropped to ards; legis ation required to achieve the goal of structural safety in the A SMALL RESIDENCE on unconsolidated fill lost its foundation when settlement dropped the Northwest and elsewhere. concrete wall and the horizontal movement added to the damage.

walks, narrowly missing pedestrians. How many more such deathtraps exist here and in other cities cannot be de­ termined. Los Angeles has recognized that there are definite life hazards in connection with building facings and overhanging objects and has passed an ordinance re­ quiring that existing parapets or ap­ pendages attached to exterior walls either be removed or strengthened so that they will resist a reasonable degree of horizontal force without becoming dislodged with danger of falling into any public way. If, after inspection, the Building inspector finds no immediate hazard, the owner is given five years in which to make the correction. The cities of the Pacific Northwest have fu lly as great, if not greater hazard to the publ ic than Los Angeles in this respect and should adopt similar legisla­ tion. Local history demonstrates that earthquakes are a normal, natural phe­ nomenon of this region that will be

March, 1951-WESTERN CONSTRUCTION 85 9

anticipated by prudent persons. T here­ fore, since cities and towns are under a duty to the public to keep their public ways (including sidewalks) in a reason­ ably safe condition it normally should be expected that this duty should ex­ tend to keeping the same public ways free from hazard of falling bodies during or following earthquakes. While there is a dearth of judicial decisions of record relating to liability with reference to earthquakes there are a number of estab­ lished legal rules that furnish analogies and guide lines on the subject, such as those set forth by the Bureau of Gov­ ernmental Research and Services of the University of Washington in its memo­ randum entitled "Liability Resulting from Projections and Falling Objects Upon Public Ways with Special Ref­ erence to Earthquakes." In addition to l.ife hazards related to LEFT-Unsupported by any adjoining building, the corner of this structure moved out from under the exterior of buildings, there are many the roof the distance indicated by the crock. phases of the problem that are related to the structures themselves and things RIGHT-Heavily looded floors resulted in the diagonal movement ot the corner of this building they support. In some cases these con­ which olmod resulted in collapse. The wall bowed out 6 in. cern the hazards of partial or complete collapse with attendant losses. The brick face of a 3-story downtown Where two buildings of different heights mill-constructed parking garage was existed adjacent, the higher one bat­ Loading of floors fractured at numerous locations during tered against the lower and was frac­ The effect of a heavy floor load on a the quake. Brick moved outward y.( to tured or broken above the top of the low structure must be considered if the ~ in. along many ol these points of building. Where two buildings of ap­ building is to retain its good health. One sheared mortar. Brick arches over small proximately the same height existed to­ 5-story warehouse structure on 1st Ave. windows were broken and the keystone gether and an open space occurred S. in Seattle was partly occupied by a almost dropped out of two. These two beyond one, the building was pushed heavy hardware firm that carried a stock were repaired and the structure face was into this open space and the front walls of metal that loaded the mid-story area given two coats of paint! lt remains in were fractured on the rebound by tensile thoroughly. After the quake the front a state of "suspended destruction" that forces. wall was broken from the side wall, and will probably proceed to failure under a Two-or-more-story store buildings the side wall was bulged out at its mid less intense shock than the one on April having the street face open or glassed in, length about 5 to 7 in. at that mid-build­ 13. with small columns and no bracing in ing story height. Further shaking would Buildings constructed without ade­ the plane of that face were fractured probably have brought complete col­ quate space between them battered to­ horizontally at the heads of the first lapse. Since this loading was on one side, gether creating clouds of dust, pulling story windows and were starting to pivot also, of the large structure, torsional away roof flashings, knocking trusses off to failure on the narrow front columns forces were doubtless involved. their seats and fracturing fire walls. and small corner sections. One-story stores and garages built (1) with long­ span joists, (2) rafters or trusses un­ BECAUSE roof joists were not anchored lo the woll, the framing pulled away and the roof col­ lapsed. Tops of the parapet wall shook loose and fell onto the sidewalk. anchored to the tops of the walls, (3) having no continuous reinforced con­ crete bond beams, and (4) having no columns or pilasters to take the addi­ tional thrusts that occur, failed by the walls moving out or by the trusses mov­ ing off their seats. Unbraced, high store fronts built as thin walls on inadequate steel beam lintels pivoted or rocked on their narrow supports but in most cases stopped short of disaster, awaiting the added push of aftershocks that didn't occur. These street fronts should be de­ signed as rigid frames and the structures should be given lateral stability in some acceptable manner determined by the structural engineer. Good masonry is strong Modern masonry buildings of rectan­ gular plan built with strong mortar on adequate foundations showed inherent strength with little or no cracking. Their minimum of weakening openings, their well-braced roof systems, and in the larger buildings their continuous con­ crete bond beams enabled them to with­ stand the movements satisfactorilv. However, this satisfactory performance this time should not give the over-confi­ dence that they will do so again.

86 WESTERN CONSTRUCTION-March, 1951 10

To withstand seismic forces, every structure must be so constructed and braced that it will move as a unit within the elastic limits of component mate­ rials. This means that not only bond beams are needed but that also strength­ ening steel reinforcement is required both horizontally and vertically in the walls and foundations, placed according to an adequate structural design which includes horizontal diaphragms or brac­ ing installed at the roof or plate line. Steel joist anchors and ties for rafters and gable ends are required by most codes, but it was surprising how many damaged buildings were found without them, after the earthquake. Without secure ties between masonry and wood construction, movement of the wood framing can occur at a different rate or period of vibration than that of the masonry, resulting in damage or demo­ lition of part of the structure. This type of failure was the basic cause of much of the early destruction experienced in this quake. Unreinforced brick chimneys, as has been stated, behaved badly. More than 10,000 chimneys in Northwest Washing­ ton required repair. Two thousand were estimated in Centralia and 1,351 were counted in Chehalis. Whether they merely turned in their steep or fell off their perch, the hazard to the public was the same. Far too many chimneys fell, some into the buildings to create ha,•oc in their path, others dropped onto the ground alongside. Still others were fractured badly, with heavy sections poised above the buildings awaiting the usual aftershocks to send them crashing through the roofs. Chimneys, like build­ ings, can be designed to resist earth­ quakes. All it takes is the will to do, and a competent designer. Appraising concrete damage Comparati\'ely little visible loss was suffered by reinforced concrete build­ ON THIS SCHOOL building at Chehalis the action of the eorthquake broke out the masonry ings, though they too can be damaged filler walls In this concrete frame with complete separation from beams and column. if not properly designed and built. They can be cracked in ways which to the lay beams or slabs back of these bulged pended destruction" to complete failure. person are unimportant but which to areas to find out what really has hap­ The little-anchored, d:imaged columns the trained eye of the structural engi­ pened, and without remembering that broke from their moorings; the heavy neer who is experienced in seismic mat­ structures damaged in one quake pro­ concrete slab carrying the filled tank ters are definitely weakening. This is ceed toward failure in the next, it is crashed down through the concrete roof especially true when the buildings have likely that some of these structures have to the floor below. As it fell, the reaction their exterior frame concealed by veneer been weakened and left to fail and cause of the surging water and the sliding tank coverings making ready inspection of heavy damage or loss of life in the next kicked the slab back over the head house the concrete frame impossible. quake. of one of the elevators. The sliding tank In engineering, as in business, there That such suspended destruction does broke over the superstructure of the is no substitute for experience. It is easy occur was illustrated by one failure in other elevator, driving it, the elevator for the uninformed, inexperienced man this quake. In the 1946 earthquake a and tons of water into a heap at the to pass over the damage unrecognized. heavy reinforced concrete column and bottom of the shaft 7 stories below. By Training, experience and integrity slab framework supporting a 50,000-gal. some miracle the men working on the should be the basic recommendations wood stave water tank 20 ft. above the floors below had gone down on the ele­ for an engineer when being considered roof of a large 7-story cold storage ware­ vator to lunch S minutes early that day for such special investigations. How­ house was cracked at the base and the or they, too, would have been included ever, when cost is involved, it is unfor­ top of the columns. The tank structure in the heap. The cost of extensive rein­ tunate that there are penny-wise owners was located at the approximate center of forcement or even the complete rebuild­ who seemingly will employ the person the roof and was flanked on each side ing of the tank structure in 1946 would who will tell them only what they want by an elevator headhouse. The building have been far cheaper than the loss to know or hear, regardless of the facts. was on piles in 611 along the waterfront. actually suffered I It may be easy for the uninformed to The damage seemed unimportant so In Longview and probably other pass up the tell-tale cracked stone, the nothing was done about it other than places, too, connections of reinforced spalling or bulging terra cotta facing to clean out the breaks and fill them with concrete columns to foundations and to over structural connections and the win­ gunite. beams of structures which had not been dows that break during succeeding days In the April 13, 1949 quake, this struc­ designed to resist the combined bending or months. But without exposing the ture, weakened at the points of greatest and direct stress due to earthquakes virnl connections between columns and stress proceeded from its state of "sus- were fractured, the enclosing concrete

March, 1951 - WESTERN CONSTRUCTION 87 11

in their frames due to the deformation of the buildings. This introduces a serious question of code adequacy as it relates to temblors, for in these in­ stances, what should have been open avenues to safety were actual areas of hazard within which those seeking to escape could have been trapped. Had the quake caused greater damage or had fire resulted, these places could have been the locations of many deaths. Waterfront structures In this quake, as in previous quakes, waterfront and similar structures were particularly susceptible to severe move­ ment and damage. They were also af­ fected in the same manner as structures on direct-bearing footings, but due to the flexibility of long piling, a greater lateral deflection and consequently a dif­ ferent period of motion occurred. Sub­ ject to the particular characteristics of the earthquake, it is possible that the LEFT-Water and sewer lines fractured with pollution inevitable unless break is uncovered. harmful effects of seismic action on free­ RIGHT- Movement in soft ground pulled open these conduits in spite of locknuts. standing structures supported on long piles may be materially reduced due to the pile flexibility, but the evidence in was spalled from the steel reinforcement hard to find. Stair slabs, on which the and the steel was subjected to such loads this respect was not conclusive in this steps are superimposed, are rigid units quake. that it bulged out beyond the column and usually extend from floor to floor line, a spectacular damage. It was for­ either continuously or in two Rights In design procedure, where such tunate that, although this earthquake with a landing between. Since in the structures are connected to adjoining was of high intensity, aftershocks did motion of a building the upper floors structures on earth or on piling which not occur so comparatively little of this is materially restrained by earth fill, type of damage was seen. especial design consideration must be given to connections between such Repair work is slow structures. Different periods and di£. It is significant of the penny-wise ferent amplitudes of movement tend to thinking of people that relatively few occur that can and did in this quake examinations of the bulging or cracked cause rupture and damage along these areas of building facings have been made lines of connection in a number of or..o rdered. It would seem that the own­ waterfront structures. ers should want to know that their in­ The effects of earthquakes on friction vestment was safe and not "on the piles, bulkheads and fills, together with skids." the subsidence of such fills are matters E levator shaft walls are especially sub­ logically associated with waterfront ject to damage, due to the rigid char­ structures. Seismic vibration of natural acteristics of such tall, rectangular units. and artificial fills is deep-seated, and These characteristics often conflict with often results in consolidation of mate­ the flexibilities of adjoining areas and rial that otherwise would take many thus cause trouble. Not only did the years to accomplish, starting at a con­ shafts suffer severe cracking in this siderable distance below the surface. In quake, but also by their action as verti­ this earthquake such consolidation often cal girders they brought additional brought a settlement of up to 8 inches in forces into play, which damaged nearby fills around and under structures, and 4 structural parts of the building. to 6 inches in friction piles under load, and dropped the ground level around Problems of elevators bearing piles a similar amount. This con­ Relative rigidities of elevator shafts solidation around heavily-loaded friction must be carefully studied in the seismic piles increases the bearing capacity of design of structures so a uniformly-re­ the piles, but without load the piles tend sisting building will result. One would to rise during the earthquake. ordinarily think an elevator a safe place Subsidence of fil led ground due to the to be in a quake but a number of them earthquake caused breakage of water, were rendered inoperative immediately, sewer and other buried lines serving through their supporting cables jumping structures, with consequent great dan­ from their sheaves, through counter­ ger from fire. It is therefore pertinent weights being projected from their to say here at the risk of repeating else­ guides, through jamming of operating WATERFRONT STRUCTURES supported on where, that particularly where facilities equipment, or through cage guides be­ piles driven into fill material shows a differ­ extend through bulkheads and exist at ing twisted and torn loose by building ential settlement of 8 in. on the fill side. other places where shear stresses may movement. In one warehouse most of be occasioned by fill subsidence, the the foregoing occurred to one elevator; often move more than the lower, and in hazard of piping breakage could and the vibration started the elevator going different rates and directions, the stairs should be reduced by installing these up and the counterweight down and it become in effect battering rams break­ lines with unbreakable pipe having flex­ ended by all crashing together. Fortu­ ing the opposing structural members ible joints where necessary. nately no one was in it. within their zones of influence. Stair wells were commonplace areas Means of emergency escape from of failure within a building, in this quake buildings were cut off in a number of Three-part article to be concluded in the as in most others, and the reason is not instances by the jamming of fire doors April issue.

88 WESTERN CONSTRUCTION-March, 1951 12 Reproduced from Western Construction, v. 26, no. 4, p. 90-92 (April 1951)

Third and Final Installment: Lessons in Structural Safety Learned From the 1949 Northwest Earthquake

A LTHOUGH well-con­ By HARLAN H. EDWARDS built to be weaklings. As spindly, weak­ kneed, heavy-headed a nd overgrown structed and thoroughly7braccd wood Chairman, Earthquake Committee frame residences firmly attached to sub­ specimens of purportedly good architec­ Seattle Section, American Society t ure many of our schools costing mil­ stantial foundations have withstood all of Civil Engineers earthquakes in this country with little lions of doll ars can and probably will be damage, the April l3 quake demon­ deathtraps for the youngsters, come a strated again that departures from good quake, a disproportionate number of strong quake when school is in session. practice pay the penalty. The unrein­ schools su ffered severe damage. It was Damage to schools on April 13 was forced concrete foundations of one group said of the California schools following widespread but generally not spectac­ or homes being built on fill ground in the Long Beach earthquake on March ular. It did not approach the total de­ West Seattle failed utterly and miser­ 10, 1933, "the cities have accumulated struction suffered by the schools in the ably and showed that the earth on which in the guise of schoolhouses, the most Long Beach earthquake but the tell-tale a building rests is also a part of the foun­ shocking collection of deathtraps that fracturing and movement of wall on wall dation and must be firm and thoroughly ever disgraced a metropolis. The Long were there, mute evidence that a few consolidated. Beach earthquake was nicely timed and aftershocks would have done the trick . . graduated to expose the condition with­ Few, if any schools in Washington, how­ Needs for wood frame structures out exacting the penalty, at least as far ever, have been strengthened since the Buildings must be securely bolted and as the children were concerned, but if the shakeup. braced to their foundations. [f the first schools had been occupied it would have Lessons in school construction Aoor is set on posts, on short studs or on been one of the greatest catastrophes in low, dwarf walls, these supports must American history. The casualties would The lesson for educators and others be strongly braced; otherwise they have been numbered not in hundreds, responsible for school construction is merely act as pivot points on which the but in thousands or tens of thousands." very plain, and the results observed heavy structure moves to failure. The So might it be said also in Washington point up three courses of action, all of which should be worked at vigorously shocks of this quake were such that only and Oregon, and in practically all other a few homes slid off their £oundations. parts of the country, should a similar for safet{s sake. quake occur. I. A careful inspection should be Buildings must be diagonally braced made by exper ienced engineers to lo­ in the frame, or by diagonally-placed Schoolhouse architecture as developed cate potential hazards in existing build­ solid sheathing extending from plate to over the years has estahlished a pattern of design, arrangement and ornamenta­ ing,;, and action should fouow to elim­ plate, thoroughly nailed to a ll bearings. inate them. Chief hazards during a mild Braces are most effective i( they are the tion which almost invariably has been followed, regardless of location. High quake are brick gable ends, parapets, continuous 1 x 4 or 1 x 6 type or larger cornices and chimneys, in addition to let into t he plates and studs and well ceilings and large rooms with many high the entire structur e if it is weak. At spiked to each hearing. The "cut-be­ windows create a structural shell which Lafayette E lementary School in Seattle. tween" type of bracing often permits is unable to resist the lateral force of building movement to take place before earth shocks unless it is very strongly it comes into solid bearing, resulting braced. Ornate entrances, usually em­ in broken plaster and a racked structure. bellished with heavy and often loosely A BRIEF OUTLINE of the complete To resist torsional or twisting forces placed terra cotta, brick and stone have report prepared by the Earthquake bui ldings should have diagonal bracing been first to fai l and rain their death­ over the ceiling joists in attics, extend­ dealing load upon the children leaving Committee, Seattle Section, ASCE, ing from corner to corner of the struc­ the building. as it is being published in W esfern ture, again well spiked in place. With respect to seismic forces, school Construction is as follows: Throughout the area affected by this buildings almost universally have been FIRST INSTALLM ENT (Feb.issue)­ An on-the-spot account of the quake BRIDGES damaged by the q uake. Left- Hori­ characteristics and damage to vari­ zontal reinforced concrete struts between viaduct ous types of structures as back­ ond trestle in Spokane were destroyed by dif­ ferential movement of the structures. Below­ ground for recommendations to be Adno bridge over Chehalis River moved perpen­ presented later; a discussion of the dicular to center line of rood lo bend pin plates effects of this quake as compared on all shoes. to others. SECOND INSTALLMENT (March issue)-Facts on how new structures can be built and old ones strength­ ened to become earthquake-resist­ ant, based on analysis of damage by the Northwest quake. THIRD INSTALLMENT (this issue) -Recommendations for a new ap­ proach to the design of structures in areas subject to earthquake ha1- ards; legislation required to achieve the goal of structural safety in the Northwest and elsewhere.

90 WESTERN CONSTRUCTION-Apr11, 1951 13 a typical 2-story structure of early days (now replaced) the east and north brick gable ends fell outward. The north end fell at the doorway where according to school routine pupils exit at 11 : 55 a. m., the time of the quake. Castle Rock School was in session and the students starting to leave for lunch when the quake occurred, sending a rain of brick from the gable end down upon them, killing one boy. The north parapet at the Lower Co­ lumbia Junior College at Longview toppled two stories to the sidewalk entrance. Some students were inside at the time and lived through falling plaster and shattered plate glass. This was a rented building used "temporarily until some future time." Thus the town's worst damaged building was used, though not designed, for school pur­ II poses. I From cornices at Central Elementary in Seattle and at similar schools in many other cities assorted sizes and numbers of bricks and stones catapulted down. Only gross disregard of the history of earthquakes permits beauty and sym­ metry to transcend safety. Chimneys are the telltales of mother earth's movements. A quiet antic both-

TYPICAL of pre-1900 buildings, this toll thin wall ond unanchored gable were easily knocked out by flexing of wood structure. Crock to left shows side wall about to foil.

stories below. In Castle Rock, Wash., forced by the courts time and again, the elementary pupi Is vacated a 3-story sending to prison those found to be at frame building and double-sessioned in fault such as was done with the con­ the Junior High School. judged by ex­ tractor and building inspector following perienced engineers to be more haz­ the Pasadena, Calif., grandstand disaster ardous than the elcmcman· schoo 1. in 1925 in which 9 spectators of the 2. Continuing instruction and drill Tournament of Roses were killed. These should be given concerning pupil con­ responsibilities should be reiterated in duct during earthquakes and other codes, and to establish them, the several CONNECTIONS between structures must be emergencies. parties involved should be required to rigid enough tha t both structures move os o 3. Adequate safeguards should insure certify in writing prior to final approval unit or be separated so they move indepen­ the structural integrity of each new of the structure by the building depart­ dently. Above, damaged base of on unbraced ment that the work has been done in column. school. At best, heavy masonry units on top are dangerous. Modern architecture accord with the plans, specifications and needs no such ornamentation, but bond building codes. ers few well-built stacks but down they beams alone in masonry walls are inade­ come in a violent vibration, laid out flat quate. 1n addition a complete lateral Conclusions across the playgrounds, dropped down bracing system is required, designed by Study of the effect of the earthquake through roofs into toilets and class­ a structural engineer or architect ex­ of April 13, 1949, together with the ex­ rooms, all spelling death to the children perienced in seismic matters. The build­ periences of other localities, supports the below them. ing and all its parts must be constructed following conclusions: and interconnected so that neither lives I. The entire Pacific Northwest west Gingerbread versus safety nor dollars will be placed in jeopardy. · of the Rocky Mountains, and particu­ The most dangerous spot during a Existing structures can be examined, larly the area west of the Cascade Moun­ mild quake is just outside the entrance, tested, and analyzed to determine their tains, is a seismic area subject to strong the place where gingerbread architec­ performance in an earthquake, and motion earthq11akes. ture reaps its casualties. But other places means of strengthening can be designed 2. To minimize loss of life and prop­ can be dangerous, too, for a jolt of by engineers trained in this specialty. erty, all structures used by humans greater force or longer duration tends to 1£ cracks or distortions in walls, or other should be designed and built to provide "bring down the house." At Puyallup indications of damage appear, it is ad­ reasonable resistance to seismic forces. High School it has been told how the visable to have and it should legally be 3. The design and construction of all unanchored ceiling and roof beams over the owner's responsibility to obtain such structures, including those built by the stage slipped off their supporting a checkup, and to follow the recom­ local, state and fed_eral bodies, should be masonry walls and dropped to the stage mendations made. in accordance with the requirements of of the auditorium. At the Rainier Ele­ The owner, engineer, architect, con­ an adequate, modern building code. mentary School in Oregon a classroom tractor and public official all have defi­ 4. Adequately designed structures of of hollow tile construction split away nite legal responsibilities to see that the steel, reinforced concrete, reinforced from the main portion of the building design, construction and maintenance of masonry and wood can be earthquake and only conjecture can fix the added structures wi ll make and keep them free resistant. temblors needed to throw classroom, from hazard to the public. These re­ 5. Adjoining structures or adjoining contents and all into the yard three sponsibilities have been defined and en- parts of the same structure are subject

April, 1951-WESTERN CONSTRUCTION 91 14

to differential movements and hence to damage through dynamic contact, ten­ sion or torsion unless t hcv are ade­ quately anchored, braced, or· sufficiently separated. 6. Inadequately anchored unit mason­ ry partitions, filler walls, and veneers of the several kinds arc \'ldncrable to dam­ age or destruction by an earthquake and if only slightly damaged or weakened by one quake, they may be a serious po­ tential hazard during a subsequent relatively mild quake. 7. Chimneys, parapet walls. cornict·~ or other members cantilevered from the general structural mass arc particularly subject to damage by seismic movement and where used should be especially de­ signed and be securely anchored to their supports. 8. Due to their stiffness or rigidity. elevator shaft walls are especially sub­ ject to damage and are capable of dam­ aging adjacent clements. They should be designed to resist horizontal forcrs proportional to their rigidity. 9. Due to relatively high rigidities in STREET FRONTS and parapets must hove strong support. Building under construction above was planes where relatively little other rig­ entirely inadequate. At left, note light I-beam bearing on thin veneer with concrete block above idity occurs, walls of stair wells and for bock-up only. At right, note thin support for the front wall, giving no lateral stability. stairway slabs themselves are particu­ larly subject to damage in an earthquake. gas, refrigeration and h•~ating lines, w11h factor in the above-mentioned code be Careful analysis should be given these serious consequences. t\ll such piping determined for any area by the zone of elements to provide correspondingly re­ should be secured by supports from each earthquake probability established by sistant strength, and where the condi­ side additional to vertical suspenders the Coast and Geodetic Survey. tions are too highly indeterminate, slip with due allowance for expansion and 6. That, due to the public hazards dis­ joints should he pro,·ided. contraction of the system. Similar re­ closed, legislation be enacted requiring 10. Soil conditions and the ~trength straint should be given to heavy ventila­ potential earthquake hazards to be of foundations are vital elcmcms affect­ tion fans, air and water tanks and similar abated within a specified maximum time. ing the abilitJ of structures to resist equipment in a building. 7. That legislation be enacted requir­ earthquakes. On soft ground it is essen­ 13. Suhsidence of filled ground due to ing owners of structures used hy the tial to tie footings together ~ccurcly the vibratory action of earthquakes can public or located along public ways to either by strong, stiff struts or hy a con­ cause breakage of water, sewer and bear responsibility for damage to the tinuous slab. other lines serving a huilding supported property of others and for injury or loss . 11. Water tanks supported by build- on piles or having deep foundations, and of life occasioned by their structures or 111gs are not only subject to the hazards can damage lines cx1ending from hard parts of them due to seismic disturb­ of other cantilever members but have ground into such unstaule soil. Such a nce. the added hazards of dynamic movement breakage hazards can he reduced by us­ of the liquid in conjunction with the ing flexible joints and by using pipe that In conclusion seismic forces, which can se,·erely stress is capable of withstanding the differen­ Seismic shocks have been of common the building. Especial analysis should be tial motion. occurrence in the Pacific Northwest in made of tanh, lank structures, and the recent years ( 155 have occurred in the building memhcrs surrounding and sup­ Recommendations Pacific Northwest states since 1841, and porting them. On the basis of the foregoing findings 30 in the last 10 years) and therefore 12. Suspended piping is subject to and obsen·atJons, the following recom­ they should no longer be considered as sidcsway and endsway. In strong earth­ mendations are made: "Acts of God." quakes this sway may cause the rupture I. That useless, superficial and dan­ It is obvious that buildings have been of fittings such as on fire sprinkler lines, gerous ornamentation be deleted from built so they can be shaken down in an plans or removed from the structure. earthquake, and equall y obvious that SUPERFICIAL damage was costly in high 2. That the basic design be such that they can be built so they will hold to­ structuru which fleud markedly. Interior par­ rigid resisting units arc provided where g.:ther under similar circumstances. Re­ titions lost their plaster and fractured. Note needed, so that differential movement sourceful engineering in the specialized vertically bowed condition of this interior wall. of various masses can be properly pro­ field of seismic design of structures and vided for and that torsional movement the cooperative interest of and intelli­ can be resisted or eliminated. gent undcrstandi11g by capable archi­ 3. That ultimate economy be con­ tects will result in earthquake resistant sidered in addition to safety. In the structures often at little, if any, addi­ architectural and structural design, if tional cost. advantageous. conventional heavy mate­ Guided by the modern seismic design rials should be discarded for modern section of the Pacific Coast Uniform lightweights, particularly in the upper Building Code, some owners arc making por tions of the building. their structures more safe to use a nd 4. That the seismic design sections of less costly to maintain. It is hoped that the 1949 and succeeding editions of the many more will learn the lessons taught Pacific Coast Uniform Building Code be by earthquakes and do likewise. Prob­ adopted by all governing bodies a nd that ably 5,000 persons in the Pacific North­ a state organization be created to secure west arc living today and property dam­ compliance in all areas not under the age of $100 million was spared solely jurisdiction of city or county building because the quake of April 13, 1949 did departments. not last a little longer. Next time we may 5. That the minimum seismic design not be so lucky! -The End

92 WESTERN CONSTRUCTION - April, 1951 Reproduced from Building Standards Monthly, v. 18, n o. 6, p. 4·11 (June 1949) 15

Page 4 BUILDING STANDARDS MONTHLY

Reporting the Northwest Earthquake

JUST before noon on April 13 Seattle ond o 150,000 squore mile oreo of western Washington experienced the most destructive eorthquoke in the history of the region. The Pacific Coost Build ­ Damage to Buildings ing Officials Conference requested Clyde H. Dirlom, chief build• ing inspector of the Los Angeles County Department of Building and Safety ond plan-checking director of the Conference, and By CL YOE N. DIRLAM Fronklin P. Ulrich, chief of the Seismologicol Field Survey, United Chief Building Inspector States Coost and Geodetic Survey, to visit the scene of the 'quake Los Angeles County Deportment of Building & Safety and report on the aspects of the disaster which would be inter· esting ond instructive to building officials and all those concerned with safety regulations in construction. Mr. Dirlam reports on the N accordance with instructions, I visited the Pugel Sound damage to buildings from the standpoint of the building official. I area for the purpose of investigating the damage to Mr. Ulrich reports the earthquake from the scientific point af buildings and other structures following the earthquake view. Bath papen are important additions to bosic earthquake on April 13. I arrived in Seattle on the morning of April data. 15 and spent a considerable amount of time examining and photographing buildings damaged in Seattle. Later I visited Tacoma and Olympia for the same purpose. This earthquake, which occurred on April 13 at 11 :SO a.m .. has been classed as a "near strong" shock. The epi­ center has been located near Shelton, which is about forty­ five miles southwest of Seattle. The shock was felt from Portland, Oregon, northward to Vancouver, 8. C., and was apparently strongest along the coast, the principal dam­ age having been in Olympia, Tacoma, eattle and a few smaller cities. Press notices state that the intensity ha,; been fixed at about seven or eight on the Modified Mercall i Scale. The building damage does not seem to bear out this value of intensity at the points of maximum damage. There have been no destructive shocks in this region for many years. One notable shock occurred in 1939 and two in 1946.

SEATTLE Tht> principal building damage at Seattle is confined to an area adjacent to Pioneer Square. This area was at one FIG. 1- Paropet woll of the aeeond story wall fell due to time a tide flat, which has since been filled in. The damaged lock of a11chorage and inferior masonry. structures rest on wood pile foundations. Most of them

FIG. 2-This e ntire building is constructed with a very in­ FIG. 3-This is a wood frame building resting on concrete ferior grode of masonry, weak mortor and lack of joint fill­ pien. Appore11tly the foundation collapsed, ollowing the ing. The poropet woll neor the corner fell because of d e- floor to slope ond cotopult the contents of the building fective moso11ry ond lock of anchorage. through the exterior wall. 16

JUNE, 1949 Page 5

FIG. 4---Lofoyette School in we,5t Seattle. The goble fell because of lock of adequate anchorage and defective ma­ sonry. The mosonry fell on the londing in front of the main entrance

FIG. 7-This church steeple in Tocomo hod o spire ot eoch c,orner. The spires were thrown off ond two of them went through the roof of the building.

FIG. 5-Lafoyette School, west Seattle. A large number of brick from the chimney fell in the school ploy-yard.

FIG. 8-School in Tacoma. The gable wall fell ond killed a small boy.

SCENES IN AND AROUND SEATTLE FOLLOWING APRIL 13 EARTHQUAKE FIG. 6-Lofoyette School, west Seattle. Goble ond chimney fell due to weak masonry ond inadequate anchorage. 17

Page 6 BUILDING STANDARDS MONTHLY

chimneys could easily have produced fatalities had the school been in session. It is noteworthy that the interior of the building and walls below the roof line were not dam­ aged beyond a few plaster cracks and that the building could be reoccupied with little repair work. Other school buildings in Seattle sustained only slight damage. princi­ pally from falling brick chimneys. Only two arc to be abandoned for the present. The larger and newer buildings in Seattle were only slightly damaged, mostly in the way of plaster cracks and cracked terra cotta facing. There are, however, a few loose parapet walls which will require rebuilding. The newer por­ tion of the business district is built on higher and more solid ground. There were a few breaks in water and gas mains: not enough to be a serious menace, however. FIG. 9-0lympio. Poropet woll wos knocked off ond corried Viaducts and bridges were not damaged with the ex­ o conopy to the sidewalk with it. ception of the movable bridges over the Duwarnish Water­ way. Movements of the earth banks caused displacement of the abutments. Lift bridges which were open at the time of the shock could not be closed. and those which were closed could not be opened. Tall chimneys, of which there are a number in Seattle, were undamaged and were ob­ viously not subjected to the forces to which similar struc­ tures in Olympia were exposed. Vt>ry little damage to re!'idential chimneys was observed, altliough there are many brick chimneys of more than or­ dinary height on the dwellings in that city. TACOMA Only a comparatively small amount of damage was done in Tacoma. A school building similar lo the Lafayette School in Seattle was damaged, a brick gable having fallen abow· an entrance. causing one fatality ( see Figure 81. A steel cable saddle which was being placed on the top of the tower of the new Tacoma Bridge was shaken off and fell through a barge in the channel. The earthquake cracked ground adjacent to the banks of the Tacoma Narrows caus­ ing a landslide some time after the earthquake. This en­ dangered a number of dwelling houses. Little damage to residential chimneys was observed, al­ tliough, as in Seattle, there are many brick chinmeys of more than ordinary height.

FIGS. 10 AND 11-0ld Stote Building, Olympio. Heovy sondstone wolls, weak mortor and lack of adequate anchor­ age contributed ta this damage. were built about sixty years ago. They are of brick masonry of inferior quality with a weak mortar and arc largely lacking in the anchorage of Aoor and roof joists. The story heights are high and there are generally many openings in the walls. These features, combined with the unstable foundation, together with neglect and deter­ ioration of buildings, make such structures an easy prey to earthquake forces, although it should be 11oted that then~ are many buildings of the same age in the same area which are apparently undamaged. The damaged structures com­ prise only a small percentage of the total number o( builcl­ ings in the area. Figures l, 2 and 3 show the general l ype of construction referred to. Outside of this area an old school building located at California and Lander Streets in West Seattle was badly damaged. as shown in Figur'!s 4, 5 and 6. There is a noticeable lack of joist anchors in the gables. The quantity of brick falling from the gables and FIG. 11 18

JUNE, 1949 Page 7

FIG. 13-Stote Insurance Building, Olympio. Heovy stone ornamental parapet wos thrown off far the entire length of the build ing.

FIG. 12- Stote Insurance Building, Olympia. Stone cornice ot upper righthond corner wos shoved out ond reody to collapse.

OLYMPIA Olympia is located nearer the epicenter than is Seattle or Tacoma. Damage was sustained by several industrial and commercial buildings, by the old State Building and by buildings on the new Capitol grounds. The dome on the -~'" Capitol is considered unsafe because of the shifting of a heavy stone lantern at the peak of the dome. The State I I Tnsurance Building was damaged as shown in Figures 12 and 13. A brick chimney 250 feet high was broken off 60 to 75 feet from the top and masonry fell on a boiler house and on another structure, producing one fatality. This chimney rested on a wood pile foundation on a tide flat fill . Other brick chimneys close by were similarly shallered. Figure 14 shows the wrecked 250-foot chimney. A considerable amount of damage to residential chimneys was observed, unlike the experience in Seattle and Tacoma. The press reports eight fatalities in the entire state; only FIG. 14-lndustriol plont ot Olympia. Brick chimney was four of these, however, were due directly to the earthquake. originally 2SO feet high; obout 60 feet of the top wos in each case being caused by falling masonry. The total thrown off, producing fotolity. amount of damage seems small compared to the reputed violence and large extent of the shock, and the many places of habitation within the area of disturbance. Appreciable compliance with the Uniform Building Code would have damage has been sustained by about eleven hundred dwell­ passed through this shock with practically no structural ing houses in the western part of Washington. The total damage. loss has been placed at various sums, but fifteen million dollars seems to be the average. SUMMARY One of the principal lessons to be learned from our study l. Damage in this shock was confined largely to old of building behavior in this shock is a re-emphasis on the buildings of inferior construction. hazard due to unanchored and improperly built parapet and 2. A building can be a serious menace to life through gable walls which can be thrown to the sidewalk during an falling parapet or gable walls although the total damage earthquake shock. These are usually located over the en­ to the building may be light. trances where people are likely to be exiting during the 3. Old masonry structures whch have high story heights course of an earthquake. existing hazardous walls could If and are of inferior construction and may have been neg­ be eliminated, lives could be saved when a heavy shock lected become a serious hazard in an earthquake. visits the community. Consideration should be given to the enactment of legislation tlrnt would make this possible in 4. Parapet walls should be properly designed and an­ localities where earthquakes are to be expected. chored to resist lateral forces. My observation indicates that our present Uniform Build­ 5. If the masonry parapet walls on existing buildings ing Code provisions regarding lateral force do not need lo could be removed or rebuilt through legislation or per­ be changed. It is my opinion that any structure designed in suasion, lives could be saved in the event of an earthquake. 19

Page 8 BUILDING STANDARDS MONTHLY

Reporting the Northwest Earthquake HE destructi.ve earthquake of April 13, 1949 occurred at From the Scientific Point T11 :55 :41 a.m. Pacific Standard Time ( 120th Meridia11 Time) . of View The Coast and Geodetic Survey using instrumental data from thirty.five seismological stations received by April 21. By FRANKLIN P. ULRICH fixed a provisional epicenter at 47.l O north latitude anJ Chief, Seismological Field Survey 122.7° west longitude (between Olympia and Tacoma). The United States Coast and Geodetic Survey following is abstracted from a recent press report: "The Geology Department of the University of Washington at Coast and Geodetic Survey). "The evidence o[ the existence Seattle tentatively placed the epicenter along the Bor· of this fault is the marked difference in the kind of rock deaux Fault near the junction of Lewis, Thurston and Grays on the west side which is largely hard lava while on the Harbor counties. This fault runs from Independence Creek, east side it is shale and sandstone in which original layers near the counties' juncture. northeastward toward Olympia." have been raised and folded. The extent of this fault is not (In the direction of the epicenter determined by the known as several hundred feet of glacial deposit cover the

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~ 0 .. ~ 0 .• • AKER .J \ I () ..,/ l"' ... \..J ? ( 4 0 I u S C. t. G S $CtSMOLOGICAL Fl [LO 5URY[T I ISOSEISMAL MAP j EARTHQUAKE 13 APRIL 1949 , 1,:55:41 PS T Q. \ I NT CNS ITV· MOO• Fl £0 MEACALLI $:CALE 19)1 ; A - NOT f(Ll I ' ,:, ~ ,00 : . .. ,\,. 0 .... /1...... 1 " '"''"'" "" '-u 1 I - - · ----1 .. - - -· --Jr·- - · , h-·4_ .. -41,. --·· - -,11- ···--··- _!_ - - ··~· - - -rli~ -- S M C 11• '" FIG. l-lsoseist11ol Mop--Northwest eorthquoke, April 13, 1949, prepared by the United Stoles Coast and Geodetic Survey, Seismologicol Field Survey. 20

JUNE, 1949 Page 9

earth from Olympia to Tacoma." The extent and direction of the most heavily damaged area would indicate possible movement along the fault for a considerable distance. (In the 1906 earthquake in California the surface rupture was visible for about 270 miles. I Locations of the epicenter im­ mediately after the earthquake and from only a few sta­ tions were considerably in error as the severity of the shock and inadequate time control made interpretation of records of near-by stations very uncertain. The isoseismal map (subject to revision as additional information becomes available) shows the extent of tJ1c area over which the shock was felt and also the intensities at the various places. The information for the isoseismal map was compiled from many press reports; from field investi, gations by C. K. Stiff ( engineer. F'actory Mutual Insurance Companies) and S. E. Warner I geophysicist, U. S. Coast and Geodetic Survey); from a special questionnaire to building inspectors in the damaged area and regular ques· tionnaire covf'rages made by State Collaborators in Seis­ mology for the Coast and Geodetic Survey: Professor Harold A. Culver, Pullman, Washington; Dr. Vernon E. Scheid, Moscow, Idaho; and Professor E. L. Packard, Corvallis, Oregon. The isoseismal map shows that the shock was felt over an area in the United States of approximately 150.000 square miles. The area of greatest intensity extended from Granite Falls south along the east side of Puget Sound to Olympia then south through Chehalis, Castle Rock to Long­ view and east and west of this line in river valleys. In the region of greatest intensity eight deaths were caused directly or indirectly by the earthquake and at least sixty-five persons were seriously injured. Shortly after the FIG. 2--0pen-air theater: Three members af the stage earthquake the press estimated damage al twenty million crew ot Puyallup High School survey the wreckage of the dollaxs. from latter and more complete information it is stage, where the roof was caved in by the eorthquoke just believed that this estimate is entirely too small and the writer os they were leaving for lunch. Under the debris ore o tentatively estimates that the ultimate total damage will be ping-pong table and o grond piano.-Seottle Times stoff nearer to fifty million. A representative of a group of in­ photo by Lorry Dion. surance companies tentatively estimated that the total dam­ age would probably be between thirty and fifty million dol­ taking the collection and compilation of the earthquake lars. Other preliminary estimates of damage range from ttm damage as a special project which will require months to million upwards. The Washington State Superintendent of complete. 111 general. damage was confined mostly to the Schools estimated the damage to thirty public schools in less stable ground, such as marshy, alluvial or filled land western Washington as between six and ten million dollars. and to older structures, particularly old masonry construc­ Damage from an earthquake is not always immediately &)J· tion with lime mortar which was built prior to modern parent. Settlement of foundations and walls with conse­ building regulations. However, there were many exceptions quent cracking of walls and plaster may not be discovered where old buildings on firm ground and new buildings on until several months after the shock. soft ground were destroyed. There was considerable crack­ Detailed reports of all damage would be beyond the scope ing of ground. ejection of sand and water by temporary of this report. The University of Washington is under- geysers; considerable damage lo bridges, docks, water main,;

AT LEFT: FIG. 3-Building occupied by the Cohen Bog Company, 3435 Klickitat Avenue, Seattle, show· ing failure of brick veneer­ Seottle Times photo.

- 21

damaged with cracked or fallen walls an? cracked or fallen plaster. All buildings in downtown region and all school, city, county, and state offices were evacuated for fir~ mat·· shal inspection. Two large smokestacks and many chnnneys fe ll. A large portion of a sandy spit jutting into Puget Sound north of Olympia disappeared during the earthqua~e. Streets were damaged extensively. Water and gas roams broken. Train service suspended for several days. Puyallup: Injuries: Many. Damage estimated $300,000 bv building department. High school damaged severely w'ith collapse of stage in auditorium (see Figure 2.) Fish FIG. 4-Foilure of parapet wall and collapse of fire escape. hatchery damaged severely. Many buildings damaged. - Photo by U. S. C. & G. S. Nearly every house chimney toppled at roof line. Hundred;; of walls were cracked. Several houses jarred off founda­ tions. Roads were blocked for several hours. Water mains broken. Utility services were interrupted. Geysers ejectP.d water and sand. Seattle: Deaths: One indirectly. Injuries: Many serious­ ly, with scores reporting shock, bruises and minor cuts. Damage estimated between five and ten million dollars. Many houses on filled ground were demolished. A prelim­ inary survey right after earthquake showed seventy-five buildings suffered considerable damage up to S50,000 a­ piece. Many old buildings on soft ground were damaged considerably. Collapse of top of one radio tower and one wooden water tank, with damage to many tanks on weak buildings. One schoolhouse partially destroyed and closed. Many chimneys toppled. Heavy damage to docks and stores awaiting shipment. Several bridges damaged and closed temporarily. Many water mains in soft ground were broken and many basements were flooded. Telephone and power service were temporarily interrupted. Large cracks in filled ground, some cracking of pavement, and water spouted six feet or more from many ground cracks. (See Figures 3 to FIG. 5-Collopse of brick filler wall. This wall ot the Crane 6 and Figure 4 of Mr. Dirlan's article.) Campany, East Marginal Woy and Hinds Street, Seattle, boi ler Tacoma: Deaths: One. Injuries: At least a dozen. Dam­ and radiator shop, fell outward in the earthquake, ,oving work- age estimated at five million. Two schoolhouses damaged men inside.- Seottle Times photo. and closed. Many buildings damaged and parts fell. Few homes escaped some damage with many chimneys damaged and toppled. Several houses slid into Puget Sound. One and pavements. A cliff 300 feet high and a half-mile long smokestack fell. One 23-ton cable saddle thrown from top in the northern part of Tacoma toppled into Puget Sound. of tower of Tacoma Narrows bridge causing considerable Abstracts of damage for a number of the larger cities are loss. Railroad br idges south of Tacoma thrown out of line given as follows : and traffic held up for hours. Railroad tracks kinked, Auburn: Injuries: One. Damage estimated at haH mil­ buckled and sank four feet in one place. Tremendous rock lion dollars. Junior High School condemned. Four blocks of downtown district damaged severely. Fall of parapet walls and many chimneys. r Ca:tle Rock: Deaths: One. Injuries: Several. Damage considerable. One school damaged severely. Con~iderable damage in brick and concrete buildings. Many chimneys fell. Centralia: Deaths: One. Injuries: 10 hospitalized. Dam­ age very heavy-estimated at three million dollars. Col­ lapse of building walls and many chimneys. Two city schools permanently closed, Methodist church condemned, continued '3ettling of ground caused extensive damage. :Water mains broken and 5000 feet of concrete pipe in city mtake water supply damaged severely. Traffic through city still restricted one week after earthquake. Water and sand spouted from ground. C~ehalis: I~juries: Several severely. Damage: City officrnls on Apnl 20, 1949 estimated it at three million dol­ lars. City library condemned. Most downtown buildings, schools and churches damaged. 1351 chimneys found dam­ aged up to April 20, 1949. Wnter mains damaged. Olympfa: Deaths: T\~O- Injuries: Many. Damage: To~al_ estimated between five and ten million. Eight capitol FIG. 6--Collopse of 54,000-gollon wooden tonk on roof bu1Jdmgs damaged ..t~o closed. Damage to state buildings of six-story reinforced concrete cold storage plant ot estimated al two m1lhon. Nearly all large buildings were Seottle.-Photo by Horry Davis, Seattle. 22

JUNE, 1949 Page 11

sHde followed the earthquake, a half-mile section of a 300- drawn-out record with slower vibrations and that the maxi­ foot cliff slid inlo Puget Sound. mum acceleration was about one-thirteenth of gravity. In both cases the maximum acceleration was associated with INSTRUMENTAL RECORDS (STRONG MOTION) a period of about 0.3 seconds. In September 1948, the Coast and Geodetic Survey in­ SEISMICITY OF PUGET SOUND REGION stalled two accelerographs in the Puget Sound region, one A compilation of felt earthquakes shows that the Puget al the U. S. Army Engineers' Base. on the tide flats at Sound region is moderately seismic. Prior to the earthquake Seattle, and the other in a small building adjacent to the of April 13, 1949. there have been within the past ten years, Transportation Building in the central part of Olympia. one earthquake of intensity VI II and three of intensity Vil This is on filled ground. Figure 7 shows the records of as shown in Table I. this earthquake from these two stations. The accelerograph does not operate continuously but the earthquake itself sets TABLE 1- SEISMICITY OF PUGET SOUND REGION off a trigger device to cause the instrument to operate. This Felt Area trigger device is set to operate when the earthquake reaches Date Locality (Sq. Mi.I Intensity Remarks a certain intensity (nonnally at a point just before cracking --- Nov. 12, Few miles 60,000 vu Felt over most of of plaster). The instrument is a high speed recorder and 1939 northwesl Washington a n d automatically stops after about 75 seconds of operation but ..>!Olympia norrhwest Oregon will continue to operate if the earthquake continues. After stopping it is ready to operate again until the photographic Apr. 29, 3ou1heast 50,000 VII Fell over most of 1945 .,f Seaule Washington and paper is used up or for a total registration of about ten nor1h Oregon and minutes. Inasmuch as the earthquake has lo reach a pre­ west Idaho. determined intensity before the instrument operates, the in­ Feb. 14, About 20 70,000 VII Fell over most of ~lrument does not record the first small vibrations but it 19-16 miles west ~ ' ashing1on, north· will record the strongest vibrations which normally are too of Tacoma. west Oregon severe to be recorded on sensitive seismographs. On the southwesl Brilish records are Lime scales showing the speed of the record and Columbia. intensity scales showing the amplitude of motion for O.lg June 23, West of 100,000 VIIJ S1rongest shock or one-tenth of the acceleration of gravity. The records 1946 Bellingham on record to that show that the principal portion of the Olympia record lasted and possibly date in the Puget in British Sound area. about 23 seconds, that the vibrations were very rapid and Columbia. that the maximum acceleration was about one-fourth of the acceleration of gravity. The Seattle trace shows a longer (Continued on Page 16)

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r---- g 1----~. ""i------"---.""'-'-".r... ~-' .-.--1._.. ~-...... -..._ ...... : ~ ...... ~,.. . - :. - ·a .,.,:v' ~ ··'-...~"--,~...... _:1,,,,.4~ ~ ..,.-,~~- _,., •

FIG. 7- Principal ports of records from United States C,ost and Geodetic Survey strong. motion seismographs at Olympia and Seattle. 23

Page 16 BUILDING STANDARDS MONTHLY

TABLE IX - COMPARATIVE DATA PER INSPECTOR EMPLOYED (Continued)

OPERATI NG COST REVENUES RECEI VED CITY Building Plumbing Electrical Smake Building Plumbing I Electrical ] Smake Atbnu S 8.091.81 i "/, 5,65;.; I ~ <,,99!.0S 5.0?2.U 11 ,260.61 J0.188 ..11 9.60H I 11 , H i.90 Detroit >.S l2.77 4.4Z--L10 USS.OS 1.5)9.1 ?• ;,899.98 4.455.80 6.Hl.37 12. 78• Kansu City 4.90l.66 l.604.H J.026.20 Lo, Angele• 10, ;2;.z9 U 9UJ 5.801.l I 5.SH.H 11.849.60 4,486.64 4,308.9 1 1?5.00 Louiiville ;.000.00 10.946.58 IS,056.60 8,695.65 1,475.00 !\,h•mphi, 6."0%:!1 j,;50.Jj 1:szo:00 17.433.75 9. 14S.66 9.195.60 ~li.1mi 5.849.75 6.000.Z! 6.01;.ss 9.757.26 9.909.6 1 8.432.6 1 f\li)w;1ukte 5.327.77 6,308.40 0 USJ.45 l\

• Op,rrau~d '4'lth p.utial staff durin1,; rst part o{ t h~ )'l".lf.

DEATH OF F. D. HOLMES Because of this activity and the possibility of a recurrence RANCIS D . Holmes, widely known among building of­ of strong shocks in this region, the Advisory Committee on F ficials from coast to coast for his activities with the Red Engineering Seismology in May 1948 recommended to the Cedar Shingle Bureau, died on March 1 In Ann Arbor, Coast and Geodetic Survey the installation of at least three Michigan. M.r. Holmes had been in ill health since October when he was stricken with pneumoni.a. strong-motion seismographs in the Puget Sound region. Although he traveled widely and contacted many building Only two instruments were availahle and. as previously men­ tioned, these were installed in September 1948 at Olympia and Seattle. A summary of felt earthquakes for the past hundred years is given in Table No. II. The record for the period 1856- 1933 was compiled by Donald C. Bradford and published in the Bulletin of the Seismological Society of America. Volume 25, Number 2, April 1935. The summary for the period 1934-1948 was compiled from publications of the Coast and Geodetic Survey. ln Bradford's compilation, thi: Rossi-Fore) Scale was used, whereas in the Coast and Gev· detic Survey reports, the Modified Mercalli Scale was used. The Rossi-Fore! Scale is about the same as the Modified Mercalli Scale for the first three intensities but about one­ half an intensity higher for intensities IV to VIII, inclusive. Hence, a summation of both compilations would not cause a serious error. T he column marked "?" includes those shocks where the available information was insufficient to determine a definite intensity.

TA BLE NO. II- FELT EARTHQUAKES IN THE PUGET SOUND REGION 1856-1 948 F. D. HOLMES Intensities Source Period 1 Total officials after his illness, he never seemed to recover fully ? 1 2 3 4 5 6 7 8 1856- from the effects of it, according to Virgil G. Peterson, assist­ 64 14 34 ant manager of the bureau. His death followed a heart Bradford 1933 30 13 10 13 1 179 C&GS 1934- attack after an operation. Funeral services were held 1n 43 1 4 8 1 71 Columbus, Ohio, on March 4. 1948 8 3 3 Mr. Holmes first joined the Red Cedar Shingle Bureau in Tota.I 107 15 38 38 21 13 16 2 250 1939. Since that time, he devoted all his efforts to the public relations field of the organization. THEATER CEILING COLLAPSES Fifty-four persons were injured, thirty-nine of them seri­ REPORTING THE NORTHWEST EARTHQUAKE ously, when the celling of the Park Theater, Houma, Louisi­ (Coniinued from Page 11) ana, collapsed during a performance on April 19. The man­ ager of the theater, Everett Talbot, said he was just enter­ In view of this apparently increasing seismic activity, the ing the auditorium when he became aware of a loud crack­ Coast and Geodetic Survey, in a new Seismic Probability ing sound which grew in intensity for about one minute, whereupon the ceiling came down in a sheet from the stage Map published in 1948, raised this region from Zone l to to the projection booth. The reason for the collapse of the Zone 2. (See Building Standards Monthly for March 1948.J celllng has not yet been determined. 24 25

U. S. DEPARTMENT OF COMMERCE CHARLES SAWYER, Secretary

COAST AND GEODETIC SURVEY Robert F . A. Studd1, Director

Serial No. 748

UNITED STATES EARTHQUAKES 1949

By LEONARD M. MURPHY and FRANKLIN P. ULRICH

UNITED STATES COVERNMENT PRINTINC OFFICE WASHINCTON , 1951

Fo:r sale by the Superintendent of Docu.menta, U. S. Covernment Printing Office Waahinirton 25, D. C. - Price 35 cents 26

20 U. S. COAST AND GEODETIC SURVEY

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April 13: 11:55:41.* Epicenter 47.1° north, 122.7° west, between Olympia and Tacoma, Wash. W. Felt over an area of 150,000 square miles in the United States. See map. Magnitude was 7.1 for a depth slightly greater than normal. Maximum intensity VIII was reported for an unusually large distance, about 85 miles, and mainly on soft ground with a high water table. Eight deaths were ca.used either directly or indirectly, many were injured, and damage was estimated at upwards of 25 million dollars. A school, church, and library were condemned and widely separated schools were seriouslr damaged. In Olympia eight capitol buildfogs w~re damaged with a loss of 2. million dollars. Elsewhere heavy property damage was caused by fallmg parapet walls, toppled chunneys, and cracked walls. Public utilities suffered seriously when water and gas mains were broken and electric and tele­ graph services were interrupted. Railroad service into Olympia was suspended for several days, and railroad bridges south of Tacoma were thrown out of line, delaying traffic for several hours. A large portion of a sandy spit jutt.ing into P uget Sound north of Olympia disappeared during the earthquake. Kear Tacoma a tremendous rockslide involving a half-mile section of a 300-foot cliff toppled into Puget Sound. One 23-ton cable saddle was thrown from the top of the Tacoma Narrows bridge tower, causing considerable damage. lNTE NSITY Vlll IN WASHING TON : Aberdeen.-One death. Several brick and concrete buildings cracked, brickwork fell. Scores of chimneys tumbled at roof levels. Water main cracked. Many cracked walls and chimneys; many broken dishes and windows. Adna.-Chimneys cracked or twisted. Knickknacks, books, and pictures fell; many dishes hroke. Furniture and small objects overturned. Considerable dama.ge to brick. Trees and bushes shaken strongly. Ashford.=--cracked windows, walls, and chimneys; many chimneys twisted or fell. Considerable damage. Auburn.-One person injured. Four blocks of downtown district severely damaged. Parapet walls and many chimneys fell. Junior High School condemned. Many wall and plaster cracks; many broken dishes. 27

UNITED STATES EARTHQUAKES 21

Buckley.-Part of high school building fell. Most chimneys in town toppled at roof Ii11e. Cracked plaster, chimneys, and ground. Books, plaster, and walls fell. Large trees shaken like small bushes. Severa.I brick buildings damaged considerably. Cas//1' Rock.-One death, several persons injured. One school damaged severely with brick and masonr~· falling on children. l'pper wall over entrance fell. Many cracks up to 6 inches wide in fields and on river dikes. Landslides. Many twisted or fallen chimneys and fireplaces, most falling north and south. Trees and power lines swayed. Plaster, windows, walls, and chlmneys cracked; man~· dishes broken. Cathlamet.-Chimneys fell, plaster cracked. Kmckknacks, books, pictures, and plaster fell. Pendulum clocks facing north stopped. Trees and bushes swayed violently. Centralia.-One death, 10 persons hospitalized. Very heavy damage. Collapse of building walls and man~· chimneys. Two city schools permanent!~· closed; 1 church condemned, continued settling of ground caused extensive damage. Water mains broken, and 5,000 feet of concrete pipe in city intake water supply damaged. Water and sand spouted from ground. Violent swa:dng of buildings and trees. Most chimneys either damaged or fallen. Many walls cracked, worst damage to north walls. Most walls fell to north or sout.h, some to west, very few to east; chimneys twisted clockwise. Telephone lines twisted together for many miles. Many objects moved, including pianos. Object.a moved from shelves on all walls. Large amounts of plaster knocked down. Pen­ dulums swinging east-west stopped. Man~· persons panic-stricken. Four miles southwest of town, water spouted 18 inches high in middle of field, leaving a ver~· fine sand formation for a considerable space around each hole, the holes var~·ing from I t.o 3 inches in diameter. Water spouted from inch­ wide crack 8 or 10 feet long. Caretaker on r-;ewaukum River intake noticed gas or air boiling up through wat.er in the river. Chehalis.-Several persons severely injured. Great damage to downtown buildings, schools, and churches. Water mains damaged, 1,351 chimneys damaged. City Library condemned. Twisting or fall of chimneys, columns, and monuments. Most damage to brick and masonry. "It didn't seem to make any difference in new or old construction as far as chimneys were concerned; certain paths took them all' and other places not any." Many broken windows and dishes; knickknacks, pictures, books, and plaster fell. Shifted heavy furnishings if on castors, overturned floor lamp. Oinebar.-Cracked plaster, windows, walls, chimneys, and ground. Many chimneys twisted or fallen. Some trees twisted and uprooted. Books, pictures, and plaster fell. Damage considerable. Forest.-At the r-;iels Paulsen farm, two springs appeared; the first came in the 1946 temblor and another appeared close b~· during this shock. Granite Falls.-Twisting and fall of a few chimneys, many chlmneys twisted. Considerable dama.f!;e to brick and masonry. Plaster cracked and fell. Trees and bushes shaken strongly. Hoquiam.-At least, a dozen water mains and pipes broken. Several cracked sidewalks. Con­ siderable damap;e to brirk and masonry. Many cracked windows and walls, many plaster cracks. lndex.-Three 6-inch water mains broken. Considerable damage to chimneys, twisted or fallen, and considerable damage to brick. Many cracked walls and chimneys. Books, pictures, and plaster fell. Kelso.-Two persons injured. Extensive property damage in business and industrial district.s. St.ocks in stores knocked from shelves. Three-foot section of theater corner wall fell. Many plaster, window, wall, chimney, and ground cracks. Twisting and fall of chimneys. Kosmos.-Cracked plaster, walls, windows, chimneys, and ground. Knickknacks, pictures, and plast.er fell; dishes broke. Twisting and fall of chimneys. Considerable damage to brick and masonry. Bells rung. Visible swaying of buildings and trees. Many light fixtures torn off. Objects fell west-east. La Grande.-Damage considerable to brick and masonry. Walls cracked south-north, object:­ fell north-sout.h. Chimneys fell. Plaster, windows, and walls cracked. Visible swaying of building[{ and trees. Ground cracks on steep side hills l inch wide to 25-30 feet long. Landslides. Pictures, books, and dishes fell. Lakebay.-Twist.in~ and fall of many brick chimneys. Cracked plaster and chimneys. Trees and bushes shaken strongly. Small objects and furnishings shifted; many dishes broken. Littlerock.-Many chimneys broken off and fallen to ground, very few left standing. Trees and bushes shaken strongly. Plaster, windows, and walls cracked; knickknacks, books, pictures, and plaster fell. Trees and bushes shaken strongly. Long1riew.-Two minor injuries. Thousands of dollars damage in Cowlitz County. Gable of community church fell; water main at high school broke, beams cracked in cafeteria.. Dam8.!(e extensive, but scattered, to business buildings, industrial properties, and resi on cuts along highway. Objects fell in a ll direl'lions, one piano on 11:lass cups rolled about 8 inche>< iu easterly direction. One fireplace mantle moved I~ inches from wall at one end but not. at all at other end; glass figurine resting on end of mantle that moved was thrown a distance of 12 feet, similar figurine at other end of mantle did not even tip over. Nisgually.-Da.mage considerable to brick, ma.

22 U. S. COAST AND GEODETIC SURVEY 0/ympia.- Two deaths, many per1'ons inj11red. 1%i;ht capitol b11iklin~ dama11:ed. Near!~· all larJ.(e buildings were damaii;ed through cracked or fallen walls and plaster. Two Jarsi;e smokestacki:; ancl many chimneys fell. Streets were damaged extensively; wafrr and gas mains were broken. .-\ large portion of a sandy spit jutting into Puget Sound north of Olympia disappeared during the <•arthquake. Olympia (4 miles south of).-Fifty percent of chimneys down or severely damaged; plaster and masonry walls cracked in every direct.ion. Top 50 feet of a 250-foot plant stack fell. Only one major water main broken and that was on filled waterfront ground. Objects on southwest-northea.~t :silt forced up through minor cracks in basement floors. !\Ian~· ba.,;('mc11t~ completely filled with silt, wit.h floors forced upwards until failure resulted. Loaded tanker reported moving about 1 inch vertically at about 3 cycl<'s per second; tanker wa.5 tied to dock in Puget Sound wit,h keel north-south. Visible swa~·ing of buildings and trees. ShPllon.- Most. damage t.o business buildings with some hou~es damaged. School chimne~· collapsed. Twi~ting and faJI of chimne~·s and columns. Severe Yisible swa~·ing of b11ildi11 ~ and trN·S. Few masonry walls cracked, brickwork damaged in a(('\\' b11ildinl{S. Objects swayed violcn1 I~· , chairs a11d table:- moved, pier ur<,s displaced, dishes and ot,her glassware broken. Considerable damaJ?;<' Io :,;tocks in stor<'i". Sotith Rend.-Cracked windows a11d chimneys, some chimneys fell. Many broken dishes and wi11dows. Books, pictnres, and plaster fell ; damage considerable to brick. Steilacoom.-Considera.ble damage to State Hospital, consisting of collapsed walls and other interior damage. Four chimneys fell. Some cracking of plaster, windows, and walls. Knickknacks and books fell. Merchandise spilled from shelves. Tacoma.-One death, at least a dozen injured. Many buildings damaged and parts fell. Many chimneys damaged and toppled. Several houses slid into Puget Sound. One smokestack fell. One 23-ton cable saddle was thrown from the top of tower of Tacoma Narrows Bridge, causing considerable loss. Railroad bridges south of Tacoma were thrown out of line. Tremendous rock5licle followed earthquake when a half-mile section of a 300-foot cliff slid into Puget Sound. Considerable damag<: to brirk; plast,er, windows, walls, and ground cracked. Trnino.- City Hall and every busincs~ house and dwelling suffE>red some damage. Stores and stocks damaged severely. Damage considerable to brick. Windows, plaster, and chimneys cracked. 29

UNITED STATES EARTHQUAKES 23 Tumwater.-Twisting and fall of chimneys and monument!'. Damage considerable to brick and masonr~·. Plaster, windows, walls, chimneys, and ground cracked. Knickknacks, books, pictures, plaster, ancl wall!- fell. Pendulum clocks facing south stopped. Vader.- Twist.ing and fall of chimneys, damage to three-fourths of all chimneys. Windows and dishes broken. .J?amage considerable to wood, brick, and masonry. Shifted everything, over­ turned vases, small obJects, and furniture. Wilkeson.-Twist.ing and fall of man~· brick chimneys, damage considerable to brick. Several houses moved a few inches off their foundations. Plaster, windows, and chimneys cracked. Books and pictures fell. Dishes and windows broke. INTENSITY YIU IN OREGON: C/atskanie.-Twisting and fall of chimneys. Damage considerable to brick and masonry. Overturned vases and small objects; plaster cracked and fell. J(nickknacks, books, and pictures fell. Hanging objects swung, pendulum clocks stopped. Rai,1ier.-Building shook with great violence. Rnickknacks, books, pictures, plaster, and walls fell. Twisting and fall of chimneys. Damage considerable. INTENSITY VIJ: Arlington.-Cracked chimneys. Knickknacks fell. Hanging objects swung north by northeast. Trees and bushes shaken strongly, small objects overturned. Blark Diamond.-Cracked walls, chimneys, and wallpaper. Pictures fell. Twisting of chimneys. Slight damage to brick. Bothe/1.-Cracked plaster and chimneys, broke dishes and windows. Slightly damaged buildings, plastered walls, and chimneys. Frightened people into streets. In central section of town several chimneys fell to west. Liµ:ht fixtures, pictures, and doo~ swung. Bre111erton.- One deat,h. Cracked plaster and walls, bricks cracked where steel rested on brick. Set off spriDkler system in Kational Bank of Commerce. Pulled elevator counterweights out of guides and put several out of service in Navy Yard. Visible swaying of buildin~ and trees. Cama.s.-Twisting and fall of chimneys, slight damage. Small furnishings shifted, hanging objects swung northeast. Concrete.- Severe trembling. Visible swaying of buildings and trees. One cement floor in new building cracked. Cosmopolis.-One death caused by heart attack. Cove.-All buildings creaked. Visible swaying of old frame building. Few old brick chimneys fell. Few small plaster cracks. People ran out of stores and homes. Des Moines.-One chimney cracked, many dishes broken. Slight damage. Hanging objects swung, trPes anrl bushes shaken strongly. Doty.-Twisting and fall of chimneys, several cracked chimneys. Small objects and furnishings shifted, vases overt.urned. Pictures and knickknacks fell. Trees and bushes shaken st.rongl.v. Eatonvil/e.-In east half of t,own more than half the chimneys were toppled, not so much damage in west half of town. Plaster fell in larp:e pieces in schoolhouse. Extensive damap:e to dishes. Difficult to maintain balance. Some water pipe connections were loosened, causing leaks. E/be.-C"racked chimnevs, broke dishes, shifted small objects. Knickknacks fell. Twisting and fall of few chimneys. Trees and bushes shaken strongly. Emm,claw.-Few chimneys damaged, plaster cracked. Damage slight. Trees and bushes shaken strongly. Everett.-Loaded coal car broke loose from its blocking and rolled down grade. Considerable minor damaµ:e to store !lt,ocks thrown from shelves. Pictures thrown from walls. Water tanks splashed over. Slight cracking of plaster some things fell out of bookcase. Fall City.-Several chimneys fell. Hanging objects swung north. Trees and bushes shaken strongly. Frances.-Twisting and fall of chimneys. Plaster and chimney cracks. Hanging objects swung, small furnishings shift.ed, books and pictures fell. Grapeview.-Cracked plaster and chimneys. Slight damage. Knickknacks, books, pictures, and plaster fell ; small objects and furnishings shifted; vases overturned. Electric lights and telephone wires swayed violently and long after shock st,opped. Grayland.-Some rhimneys cracked and some dishes broken. Overturned vases and small objects, shift,ed small objects. Hanging objects swung. Hob11rt.-Cracked plaster and chimneys. Knickknacks fell, vases overturned. Trees and bushes shaken strongly. Issaquah.- Chimneys cr~ked, pictures fell, small objects overturned. Hanging objects swung north. Trees and bushes shaken strongly. Kirkland.-Cracked plaster, walls, and chimneys. Some store windows broken. Knickknacks, books, pictures, and plaster fell. Larey.-Rattled windows, house shook violently. Knickknacks fell. Twisting and fall of some chimneys. La Conner.-Hanging objects swung, pendulum clocks stopped. Trees and bushes shaken strongly. Cracked a few chimneys, broke a few di~hes. Damage slight. Landsburg (one-hnlf mile east of) .-Trees and buildin11;s swayed violently. Several chimneys collapsed, some plaster walls rracked in easterly direction. Several poorly constructed buildings \\-ith old brick chimneys were damaged. Wirf'.s, parked cars, and water tanks swung west-ea.st. ~lost objects fell in ea.">t.erly direction. 30

24 U. S. COAST AND GEODETIC SURVEY

Langley.-Cracked pla.c;ter and chimneys, broke dishes. Shirted all small objects and furnishinp;s, overturned all vases. Knickknacks, books, pictures, and plaster fell. Pendulum clocks facin~ northeast stopped. Leavenworth.-Cracked plaster and walls, fall of plaster. Damage slight. Shifted small objects and furnishings. Hanging objects swunp;. Longbra.nch.-Damage slight to wood and brick. Shook small buildings hard. Plaster, windows. walls, and chimneys cracked; knickknacks, books, pictures, and plaster fell. Trees and bushes shaken strongly. Longmire.-Cbimneys cracked, knickknacks fell. Damage slight. Shifted or overturned small objects. Hanging objects swung. Several rockslides on Rampart Ridge, Eagle Peak, and Mt. Rainier; some snow avalanches occurred. Dishes fell eastward, walls cracked slightly in only one building. . Morton.-P!aster, windows, walls, and chimneys cracked; knickknacks, booksb and pict-ures fell. Dishes and windows broke, twisting and fall of few chimneys. Trees and ushes shaken st.rongly. North Bend Ranger Station.-Cracked plaster and chimneys. Knicknacks fell. Some slight damage. Cars and trucks shifted. Olalla.-Twisting and fall of chimneys. Many plaster, window, and wall cracks. Windows and dishes broke. Trees and bushes shaken strongly. Orchards.-Cracked plaster and chimeys, fall of chimney brick. Damage.slight to brick and concrete. Overturned furniture. Trees and bushes shaken strongly. Packwoorl.-Hanging objects swung, fur11ishings shifted. Chimneys cracked, knickknacks and books fell. Dishes broke. Trees and bushes shaken strongly. Packwood (north section).-Several landslides. Bells rung. Visible swaying of buildings and trees. Pe11duJum clocks stopped. Electric wires swung violently. One chimney broken off at roof, plaster on chimney broke at District Guard's house. Books fell out of bookcase. Preston.-Trees and bushes shaken strongly. Fires in oil stoves extinguished. Chimneys cracked, vases overturned, small objects shifted. Damage slight. Roy.-Plaster, windows, chimneys, and ground cracked. Several chimneys fell, windows broke. Hanging objects swung east to west. Satsop.-Cracked ground. Broke dishes. Hanging objects swung, pendulum clocks stopped. Trees and bushes shaken strongly. Furnishings shifted. Satsop (west section).- Visible swaying of buildings and trees. Cupboard doors swung open, pendulum clock stopped. Thunderous subterranean sound heard before shock, rattling heard after shock. Seahurst.-Plaster and ground cracked. Knickknacks, books, pictures, and plaster fell. Hanging objects swung, small objects and furnishings shifted. Snoqualmie.-All damage confined to brick chimneys, dishes, and plaster. Overturned vases and floor lamps. Shook coffee out of cups. Rockslides on Mt. Si. T rees and bushes shaken strongly. Start11p.-Chimneys slightly damaged. Some vases, small objects, and furniture overturned. Stevenson.-Plaster on ceiling of several store buildings cracked. Heavy light fixtures swayed with arc of about 8 inches. Groceries in stores fell from shelves. Landslide occurred at Table Moun­ tain, with dust visible for 10 miles. About eight shocks were felt. S11ltan.-Cracked plaster, walls, and chimneys. Books fell and dishes broke. Small objects shifted or overturned, hanging objects swung north. Pendulum clocks facing northeast stopped. Toutle.- Log house creaked. Trees and bushes shaken strongly. Twisting and fall of chimneys. 1Tancouver.-Cracked oil tank. Pendulum clock facing north stopped. Trees and bushes shaken moderately. Hanging objects swung east- west. Visible swaying of buildings and trees. Dishes and stand lamps fell. Some plaster cracked east-west. 1':ashon.-Cracked plaster and chimneys. Two chimneys fell. Winlock.- One injured. Damage extensive. Store windows shattered, store merchandise damaged. Bricks fell from buildings, general damage to residences. INTENSITY VII IN OREGON: Astoria.- SeYeral injured. Several chimneys fell, considerable fallen plaster, mostly north­ south walls. Wall of courthouse shifted one inch and glass dome was badly broken. Several water mains broke and flooded ba.«ements. Lamps fell, chandeliers swung, water- from fish bowl spilled on table water below rim about 1)4 inches, spilled mostly to east. Whistling subterranean sounds heara1 at time of shock. Astoria. (16 miles east of).-Man working in garden saw ground move back and forth about 3 inches in east-west direction. Slight rumble heard. Hebo.- Shifted small object,'> from shelves, overturned vases and small objects. Walls and chimneys cracked, kniC'kknack:- fell. Hanging objects swung. Hillsboro.-Shifted furuishiugs, 0Yert11rned some va.'Ses and small objects. Some pla.'>ter cracks windows and walls cracked. Twisting and fall of some chimneys. Some people made ill froru rnotio~ and nervousness. J ewell.-Cracked and t.wisted chimneys, some chimneys fell. Small objects overturned. Hang­ ings objects i,w\lll!1:. Trees and bu~he~ i-haken strongly. North Portland.-HeaYy >

UNITED STATES EARTHQt;AKES 25

Oregon City.-Pla.."t.er and chin111eys fell. Considerable merclui.ndi"e fell from shelves. Hou!Se rocked back and forth, lights swu11g southwcst- northea.-;t. Chancleli<'r and flowerpot i;wung for 20 minut.es af1er shock.

Oswe(/o.- Ha11gi11g object,- and doors swung. Shifted furni;a;hing!- 1 overturuemirrors on all four walls tilted. Plaster cracked in many areas in 'Weather Bureau building. At Weather Bureau airport station, automobilei! parked in north-south direction rolled back and forth. Pratum.-Hanging objects swung. Concrete tloor era.eked in 8 or 10 places as much as Ji inch. Floor badly damaged. , (Juinc,J.-Cracked plaster, windows, walls, chimneys, and ground. Pictures and plaster fell. 8ome damage to col1unns and monuments. Trees and bushes shaken moderately, Rockaway.-Cracked plaster and chimneys, three chimneys twisted and fell. Shifted smali objects and furnishings, pendulum clocks stopped, dishes broke. Sanrly.-Cracked walls and chimneys, cracked concrete wall in garage. Canned fruit fell. Trees and bushes shaken strongly. Senside.-Cracked plaster, windows, and chimneys. Knickknacks and pla.<;ter fell. TwistinJ!, and fall of chimneys. Hooks, pictures, and canned goods fell. Pendulum clorks stopped, hanging objects swung. Felt by people in parked cars, but not by people driving. Accompanied by a lteavv ronrinJT, and rumbling sound. · Shedrl.-l'endulum clocks faciug east stopped. Small objects shifted. Several chimneys twisted and fell. Plaster and chimneys cracked. INTENSITY Vl: Anacortes.-Felt bv all. Hanging objects swung north, pendulum clocks stopped. Few chim- ney cracks. · Ariel.-Very loud rattlinJ!, of windows, doors, and dishes. HanidnJ!. objects swung. Books fell, few cracked chimnevs. Bay Center.-Small objects shifted, books fell. " Too excited to do much observinJT,." Bel/air.-Shifted small ohjects and furnishings, broke two dishes. Car bouuced up au

26 U. S. COAST AXD GEODETIC S'(jRVEY llyak.-Rattled vtindows, doors, and rlishes. Trees and bushes shaken stron11;ly. Small object.i, allCI furnishings shifted, Power station D. C. voltmeter made line on ehart I Vi iuches long. I,011rier.-Windows rattled, hanginii; object;: swung nonhwest. Peudulum clocks stoppP.ushes shaken slightly. Few pla,;te1 cracks. Lucerne.- Rattled windows, doors, and dishes. Hanging objects swung, small objects shifted. Trees and bushes shaken siightly. Marietta.-Hanging objects swung north, pendulum clocks stopped. Knickknacks and books fell. Mercer lsland.-Slight damage. Trees aud bushes shaken strougly. Smnll objects and furnish- ings shifted. Mcmroe.- Hauging objects swung. Sliµ:ht cracking of plaster. Montesano.-Hauging objects sinrng, pendulu111 clocks stopped. Plaster cracked, knickknacks fel l. Mount Adams Ranger Station.- Visible swaying of buildings. Lanterns swung north-south. Saws and chains thrown to floor. Pendulum clock stopped. Nase/le Junction.-Hanging objects swung, some knickknacks fell. :\lotion shook loaded truck, trees, and buildings. Omak.-Hanging objects swung. Few plaster cracks. Damage slight. Ceiling lights and rocking chairs swayed. Orting.-Hanging objects swung. Trees and bushes shaken strong!)·. Pacific Beach.- Hanging doors swung northwest. l~nickknacks and pictures fell. Slight damage. Palmer.-Hanging objects swunii;. S0111e plaster cracked. Trees and bushes shaken stronp;h·. Parkway.-Hanging object;- ~wung north. Trees and bushes shaken strong!.\·. Shock preciided by loud era.ck-like blast. Port Townsend.-Pendulum clocks racing northeast stopped. Hanging objects swung northwest­ southeast. Slight damage. Subterranean sounds heard during shock. Potfotch.-Rocked buildinp;, pendulum clocks facing ea.-,t stopped. Knickknacks, books, anrl pictures fell. Prevost.-Ten fruit jars fell from shelf. Slight damage. Prosser.-Pendulum clocks stopped. Pia.st.er cracked. Knickknacks fell. Damage slight. Ot1i/cene.-Visible swaying of buildin_gs and trees. Pictures foll from wall. Ouina11/t.-Visible swaying of electric wires. Slight damage to buildings, few chimneys cracked. Ridgefield Ci miles southeast of) .-Water in cistern sloshed back and forth almost directly west-east. Seemed to go up and down about 8 inches. Rockport.-Hanp;inp; objects swung northeast. Trees and bushes shaken. Scienic.-Ranging objects swung north. Trees and bushes shaken strongly. Books fell. ,5eq11im.- Hanging objects swung eMt-west. Plaster cracked. Slight damage to masonry. Silverdale.-Cracked p!Mter very little. Pictures fell. Trees and bushe.'S shaken moderately. Skykomish.-Hanging objects swung, vases overturned. Plaster, chimneys, and walls cracked. Dishes and windows broke. Damage slight. Skykomish Ranger Station.-Slight damage to plaster and chimneys. Flower pot fell off sill, dry battery thrown off pile toward ea.,;t. Pendulum clock stopped. Snohomish.-Craeked plaster, one old chimney toppled. Merchandise shaken from shelves in stores. Trees and bushes shaken strongly. Spanaway.-Hanging objects swung north-south. Pendulum clocks facing east stopped. Shifted stove pipe, overturned vases and small objects. I(nickknacks fell. Lake was choppy. Wash.011gal.- Hanging objects swung north-south and east-west. Cracked plaster, some cracks in brick and 018$0nry walls were enlarged. Wn.sh011ga/ (a/1out 8 111ilPs fro111 highway in the Columbia Gorge, near Cape Horn).- House swayed back and forth, loose object.-, bounced around. Wires connected to house whipped up and down. Tree tops, cables, and ropes swa:verl strongly. Arm of telephone pole broke off. White Sa/mon.-Visible swayin!( of buildings and trees. Dressing table moved 6 inches south­ north. Wi/lapa Harbor Station.-Visible swaying of buildings and trees. l\lany chimnevs shaken down in Raymond and South Rend. Objects fell west- east. Pendulum clock stopped. Roari11g subter­ ranean isoundi, at time of shock. Winton.-Cracked plaster. Damage slight. Trees and bushes shaken strongly. lNTENSJTY Vi lN ORE<":O!C Anle!ope.-Hanging objects swung. Plaster cracked. Damage slight. Baker.-Lip:ht fixtures swung, small objects and furnishings shifted. Some clocks stopped. Knickknacks and books fell. Bay City.-Hanging objects swung north- south, pendulum clocks facing south stopped. Cracked plast,er and windows. Damal!e l'll il!ht. nroke wallpaper in a fe\Y homes, so111e plaster 011 brick flue;; cracked. Some canned goods knocked off shelves, broke jam and cat~up jars. Beaverlon.-Hanging objects swung. Trees and bushes shaken noticcablv. Damage slight. . Larp;e easel picture toppled. - B1,:rton and vi.cinity.- Water heard sloshing in well. Tree~. electric poles, and 30-!(allon hot­ water tank swayed. Boards on ground moved as if on water. :\lercha11cli~e fell fro,11 ,-helve" in grocery store. Old post office building swayed violently. Corvallis.-Cracked plaster in high S('hool, damage slight to concrete. Elevator ::wayed, picture" shifted, pendulum clocks stopped, rocked swivel chair. 33

UNITED STATES EARTHQUAKES 27

Ot1tler.-Knickknacks and pictures fell. Damage sliµht.. Pendulum clocks stopped, hanging objects swung northeast. Val/as.-Hanging objects swung east. Knickknack,- fell. Damage s light. Dallas (5 miles WPSt of) .-C'ouch moved. Electric light. cord swayed east- west. Dishes rattled. Delake.-Piano jiggled. Bushes and power poles shaken, wires swung. Glassware in cabinet shifted. Depoe Bay.-Banging objects swung. Knickk11acks fell, vases overturned. Dundee.-Rattled windows, doo,~, and shi11gles on roof. Telephone wires swa~·ed. Stove pipes jarred. Made obscr\'N and 01 hers ill. Eagle Creek.- \\'a.ter in pan swayed north-south. Rangi11g objects swung south. House and drain pipes creaked. Florence.-Cracked plaster. Damage sligh1. Hanging lights swung. Forest Grove.-Cracked plaster. Hanging objects swung. Trees and bushes shaken strongly. De.maize slight. l\lade some dizzy. Glenwood.-fi anging object,g swung norLheast. Electric clocks stopped. Trees and bushes shaken strongly. People rushed out.doors. Gahle.-One can of coffee fell. Hanging objects swung. Trees and bushes shaken moderately. Gable (2 miles west o/).- Swung hinged panel of radio cabinet open. Watet tumblers t.hrown off ;;ht>lves and broken. Gresltam.-Hanging objects swung, small objecl,s shifted and overturned. Knickknacks fell. ~light damage. Httbbard.-Pendulum clocks facing northeast stopped. Plaster cracked, knickknacks fell. Very s lighl damage. Keasey.-Strongly felt. Cracked plnster and broke clishes. Knickknacks and pla.st,er fell. Lacoml,.-Trees and bushes shaken st rongl.1·. Lacomb (Smiles northeast of).- Housc shaken strongly, occupants ran outside. Saw woodshed bouncing back and forth, east~wcst. Shook light wires st.rongly. Clock stopped. Lake Grove.-Rattlcd articles. Pendulum clocks stopped, vases overturned. Plaster cracked and knickknacks fell. Slight damage to masonry. J,e/,anon.-Cra.cked plaster and windows. Hanging objects swung. Mrlllin111:il/e.-Crackcd plast,er, broke dishes. Hanging objects swung north-northeast, knick- knacks fell. }·ew ground cracks. Manhallan Beach.-Trees and bushes shaken strongly. Mauning.- Plast,er cracked, knickknacks fell. Rlight damage to concrete. Ma7.frtfand.- 8hifted small objects and furnishings. Slight, damage. Marion Fo,·ks.-Light cords and pictures on wall swung. Trees and bushes shaken st.rongl,1·. M arshland.-Hanging objects swung, pendulum clocks stopped. Plaster cracked. Slight dam&gr. Moln/la.-Banging objects swung, small object.s and furnishings shifted . .Mo11mo11,//t.-Hanging object,s swung north-south, pendulum clocks facing west stopped. Plaster era.eked and fell. Sl_ight damage. Mount Angl'/.-Ha.nging objects swung ea.st, pendulum clocks facing east stopped. Small objects shifted and knickknacks fell. Mount Hond.-Plaster era.eked and fell. Slight damage. Hanging objects swung. l\·etscoll.- Pendulum clorks facing west stopped, hanging objects swung north-south. Cracked plaster and chimneys. Cans fell in grocery store. Slight damage to brick, mai;onry, and concrete. Nrwberg.-Hanging objects swung north. Plaslrr aud chimneys era.eked. Slight damage. Newberg (6 miles northwest o/).-House swayed so strongly observer thought it would leave foundation. New71orl.-Crackcd walls and chimneys. I, and chimneys. Overturned small objects. Oreanside.-Hanging objects swung. Made everyone dizzy. Ode/l.-Hanging object,s swung east-west, pendulum clocks stopped. Ca.rs moved. Orenco.-Banging objects swung, pendulum clocks stopped. 1 rees and bushes shaken strongly. Chimneys era.eked; knickknacks and dishes fell. Slight damage to brick. Parkdale.-Banging objects swung, small objects shifted and overturned. Trees and bushes shaken strong!~·. Phi/0111nlh..-nars in post-office windows rattled. Hanging objects swung north. Well ca.Yed in. Prinville.- Hanging objects swung, pendulum clocks stopped, knickknacks fell. People felt sea.sick. Redmond.-Pendulum clocks facing north i.topped. Knickknacks fell. Roy.-Cracked pie.st.er and walls, some plaster fell. l\fotion like small boat on choppy water. Safrm.-Cha.ndelic•rs, hanging plants, and bird cages swung no1 th-south. Small objects and furnishings shifted. Plaster cracked. Slight damage. Salr111 ( Weather 811Tea11 Office. at airport).-Radio tower swayed, slight damage to buildings, few walls crack0d north t,o northeast. Sa11dlaJ:r.-Car shaken strongly. Hanging objects swung. So11t·i1•s Jsland.-Felt by alJ on picnic field. Trees and bnsh<'s shaken moderately. Scan1oose.-F<'lt, by and frightened all. Windows, doors, and dishes rat.tied. Scio.-Sma.U objocts and furnishings shift.cd. Slight damage. Sheridan.-Ha.nging objects swuug, peudulum clocks stopped. Plaster cracked and knickknacks fell. 34

28 U. S. COAST AND GEODETIC SURVEY Sherwood.-Hanging objects swung north-!mirror on north wall fell and wa...; broken. Car (not in gear) rolled in eaA-we>'t dfrection a.bout 3-4 feet. Tualatin.-Shifted dishes, overturned small objects. Pla..-

THE PUGET SOUND, WASHINGTON EARTHQUAKE OF APRIL 29, 1965

PRELIMINARY SEISMOLOGICAL REPORT By S. T. ALGERMISSEN and SAMUEL T. HARDING

PRELIMINARY ENGINEERING REPORT By KARL V. STEINBRUGGE and WILLIAM K. CLOUD 36

U.S. DEPARTMENT OF COMMERCE

JOHN T. CONNOR, Secretary

COAST AND GEODETIC SURVEY

H. ARNOLD KARO, Director

U.S. GOVERNMENT PRINTING OFFICE WASHINGTON: 196S

For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, D.C., 20402 • Price 40 cents 37

CONTENTS

Page Preliminary Seismological Report______1 Introduction______1 Geologic Setting______1 Seismicity ______3 Hypocenter, Origin Time and Magnitude______6 Intensity______11 VVashington______14 Oregon______15 British Columbia______15 Modified Mercalli Intensity Scale of 193L ______15 Foreshocks and Aftershocks______16 Direction of Faulting ______. ______19 Conclusions______25 Acknowledgments______25 References______25 Table !.-Earthquakes in the Puget Sound Area., 1833- April 1965______5 Table 2.-Summary of Hypocenter Computations______5 Table 3.-Summary of Travel Time Residuals for Four Hypocenter Com- putations------7 Table 4.- Magnitude Calculations______~______11 Table 5.- Location and Description of Portable Seismic Equipment______17 Table 6.-Chronological Listings of Foreshock and Aftershock Data, April 7-May 30, 1965------18 Table 7.- Character of F irst Motion______24 Preliminary Engineering Report______. ______27 Introduction ______~ ------27 Description and Analysis of Damage______27 Strong Motion Measurements______43 Acknowledgments______43 Table 8.-Composite of Strong Motion Instrumental Data (Acceleration)_ 50 Table 9.-Composite of Strong Motion Instrumental Data (Displacement)_ 51 m 38

ILLUSTRATIONS

Page Figure 1.-Ea.rthqua.kes in the Puget Sound, Washington area., 1833-April 1965_ 4 Figure 2.- Loca.tion map of the epicentra.l area. showing permanent seismo- graph stations, epicenter of the April 29 earthquake and a. possible foreshock on April 7, 1965------9 Figure 3.- Residua.l distribution with azimuth for 120 station bypocenter solutions, depth not constrained______10 Figure 4.-Residual distribution with distance for 120 station hypocenter solutions, depth not constrained______10 Figure 5.-Residual distribution with azimuth for 25 station hypocenter solu- tions, depth not constrained______11 Figure 6.- Intensity map of the Puget Sound, Washington earthquake of April 29, 1965______12 Figure 7.-Map of West Seattle showing the damage to chimneys in the area.__ 13 Figure 8.-Loca.tion of temporary seismograph stations, epicenter of the April 29 earthquake and possible aftershocks______17 Figure 9.-Stereogra.phic projection showing the first motion and direction of faulting------20 Figure 10.-Stereogra.phic projection showing detail of the fa.ult plane solution _ 21 Figure 11.-Compa.rison of fa.ult plane solutions of the April 29, 1965 and April 13, 1949 earthquakes: A plane______22 Figure 12.-Compa.rison of fa.ult plane solutions of the April 29, 1965 and April 13, 1949 earthquakes: B plane______23 Figure 13.-Fa.ilure of an unreinforced brick gable in Seattle. The masonry fell on a parked car, injuring occupant (see Figure 14) ______28 Figure 14.-Rescuing man injured in automobile due to collapse of gable (see Figure 13)------29 Figure 15.-King Street Railroad Station in Seattle______30 Figure 16.-Fa.ilure of unreinforced brick para.pet wall in Seattle______31 Figure 17.- Unreinforced brick fell from top story at Fjsher Flouring Mill, Seattle______32 Figure 18.-The 60-foot brick chimney at the Alki Elementary School in Seattle collapsed on the one-story boiler room, severely damaging it______33 Figure 19.- Hole in the roof due to the collapse of the chimney shown in Figure 18______34 Figuro 20.- Chimney damage in West Seattle______35 Figure 21.- Chimney damage in West Seattle______36 Figure 22.-Four-inch thick brick veneer peeled off of this wood frame structure in Seattle. The galvanized metal anchors were imbedded in a bed of low strength mortar------37 Figure 23.- Glass windows broke on three sides of this 10-story building in Tacoma.. The fourth side had no wall openings ______- - 37 Figure 24.-Landslide damage to a roadbed in Olympia. ______------38 IV 39

ILLUSTRATIONS

Page Figure 25.-Some of the structural damage to a newly built precast reinforced concrete building on Harbor Island in Seattle______40 Figure 26.-Ground dropped due to the pier at the left shifting toward the water. Location is Harbor Island in Seattle______41 Figure 27.-Woodland Park Standpipe, Seattle. Typical damage to anchor bolts may be seen in next figure______42 Figure 28.-Typical anchor bolt damage at Woodland Park Standpipe, Seattle. Note that the anchor bolt has necked where it meets the concrete and tha~ the bolt failed in the threads______42 Figure 29.-Reproduction of accelerograpb records obtained at Olympia, Washington on April 29, 1965------44 Figure 30.-Reproduction of accelerogra.ph and Carder displacement meter records obtained at Tacoma, Washington on April 29, 1965______45 Figure 31.-Reproduction of accelerograph and Carder displacement meter records obtained at Seattle, Washington on April 29, 1965______46 Figure 32.-Tracing of accelerograph record obtained at Olympia, Washington on April 13, 1949 ______47 Figure 33.-Tracings of accelerograph records obtained at Seattle, Washington on April 13, 1949.------48 Figure 34.-Comparison of acceleration peaks showing the number of times acceleration reached various levels in the April 29, 1965 and April 13, 1949 earthquakes __ _ ·------49

V 40

PRELIMINARY SEISMOLOGICAL REPORT

by

S. T. Algermissen

and

Samuel T. Harding

INTRODUCTION GEOLOGIC SETTING On April 29, 1965, at 8 :29 a.m., Pacific The Puget Sound region is a geomor­ Daylight Saving Time, the Puget Sound, phic and structural depression character­ vVashington region was shaken by the sec­ ized by low rolling hills and depressions ond largest earthquake known to ha,e occupied by rivers, lakes, or the waters of occurred in the aren. since 1833. This re­ Puget Sound. It separates the Cascade port is a preliminary interpretation of Mountains to the east from the Olympic seismological data obtained from perma­ Mountains to the west. The two ranges nent seismograph stations throughout the are arches or broad anticlines and Puget world, temporary seismograph stations Sound is a broad depression consisting of established in the epicentral area imme­ a series of shales, sandstones and lavas of diately following the earthquake, intensity Tertiary age folded into anticlines and reports, and inspe~tion of the epicentral synclines. The Olympic Mountains are area. composed of folded and faulted quartzites, Seismological data available were unu­ graywackes and highly indurated sandy sually abundant. Four permanent seis­ shales probably of pre-Tertiary age. mograph stations recorded the earthquake Fringing the Olympics is an enormous at distances less than 80 km from the epi­ thickness of basaltic flows and pyroclast­ center, thus permitting the determination ics of early Eocene age ( Coombs and of a somewhat more accurate focal depth Barksdale, 1942). The Cascade Range is for this earthquake than is normally pos­ a post-batholithic volcanic complex in sible. Excellent seismograms were writ­ southern Washington but consists of the ten by three strong motion seismographs, Nevadan complex in northern Washington all located within 50 km of the epicenter. (Eardley, 1962). Felt data reports were received from loca­ The P uget Sound area consisted of a tions in British Columbia, Washington, vast erosion surface at the beginning of Oregon and Idaho. Four temporary seis­ Tertiary time. Early in the Eocene epoch mograph stations were in operation within this erosion surface began to subside and three days after the earthquake. The was subsequently covered with Metchosin widespread cover of glacial material in the volcanics with a minimum average thick­ area, reduced the operating mag1.1ification ness of approximately 3,000 feet. A of the temporary stations and is also be­ north-south trough with its axis in the ap­ lieved to be an important factor in ex­ proximate position of the present Puget plaining the distribution of seismic inten­ Sound depression had formed by the close sities near the epicenter. of Metchosin voJcanism. Eight to four- 1 41

2 COAST AND GEODETIC SURVEY teen thousand feet of sediments, known as Ice-contact stratified drift was de­ the Puget group in the Seattle region, were posited over much of the area. deposited in this trough. Liesch, Price, I. Period of alluvial valley filling and and Walters (1963) have summarized the localized peat deposition, minor Tertiary and Quaternary history of the erosion, and soil development." Puget Sound area as follows: Folding occurred in Miocene time which, "Tertiary : according to Eardley (1962), was of low A. Late in the Eocene epoch over 12,000 to medium intensity and trending general­ feet of carbonaceous shale, sand­ ly northwest. It has, in general, been dif­ stone, con.I beds, andesitic tuff and ficult to identify faulting in the Puget volcanic breccia accumulated on a Sound area because of the predominance gradually sinking coastal plain. of glacial material. In most cases faults B. During the Oligocene and Miocene have been shown in the literature as epochs about 8,000 feet of marine normal. shale, sandstone and conglomerate The preponderance of glacial deposits were deposited, probably concur­ in the epicentral area has a significant in­ rently with the extrusion of ande­ fluence on the seismic intensity observed. sitic flows of unknown thickness. Liesch, Price, and Walters (1963) have C. Commencing late in Miocene time, prepared geologic maps of northwestern the area was deformed by folds King County, Washington, and Poulson, trending approximately N70°W. et al. (1952), have presented a comprehen­ D. The north-trending Cascade and sive soil survey of the same area. I t is Olympic Mountains were uplifted hoped that subsequent work may be able to in the Pliocene. closely relate the known geology to the Quaternary : observed seismic intensity. E. The Puget Sound Basin was par­ The western slope of the Cascade Moun­ tially filled by at least three periods tains is an abrupt escarpment which rises of glaciation sepa.rated and fol­ from the lowlands bordering Puget Sound lowed by lacustrine, alluvial, and at elevations of 50 to 200 feet, to a height marine deposition of clay, silt, of several thousand feet above sea level. sand, gravel, and peat. The northern part of the Cascades is com­ F. Relative uplift of the Puget Sound posed mostly of a complex mass of plu­ Basin resulted in a period of canyon tonic and metamorphic rocks which repre­ cutting. Much of the present depth sent the basement upon which the lavas and width of the Puget Trough, of the southern Cascades were poured. I n and the valleys occupied by Lake the northern Cascades, volcanics occur Washington, Sammamish Lake, and only as a discontinuous veneer. The the Snoqualmie River, may have northwest-southeast folding in the Puget been formed during this period. Sound area consequently intersects the G. Advance of the Vashon glacier in north-south escarpment of the western Wisconsin t i me deepened and slope of the Cascades at an angle. This widened north-trending valleys. relationship has suggested to geologists Thick bodies of sand, gravel, and that the northern Cascades ''"ere bordered till were deposited over the area, on the west by a great fault. Bradford particularly in valleys transverse and Waters (1934), in the course of their t-0 the direction of ice movement. study of the Tolt River earthquake of H. Retreat of the Vashon ice occurred July 17, 1932, investigated this suggestion at least 14,000 years ago. A series of faulting and discovered evidence for a of ice-dammed finger-shaped lakes fault striking more or less north-south eroded spillways across the uplands. between the towns of North Bend and Sul- 42

THE PUGET SOUND, WASHINGTON EARTHQUAKE 3 tan. They gave the following evidence earthquakes are distributed in maximum for faulting : ( 1) At a point about 4 intensity as follows: One of intensity miles from North Bend a section of sedi­ VIII; seven of intensity VII; thirty-one mentary rock more than 3,000 feet thick of intensity VI; sixty-three of intensity dips toward Mount Si at angles of 20° or V; and eleven others for which the maxi­ more and the exposures can be traced con­ mum intensity could not be determined but tinuously to within 100 yards of the 4,000 are believed to have an intensity of V or foot escarpment of Mount Si. In the space greater. of 100 yards the thick section of uni­ Historically, the Puget Sound area has formly dipping rocks could not be bent been subjected to frequent earthquakes of into a position so that it could pass over moderate intensity. Table 1 lists the the top 'Jf the mountain in unconformable earthquakes with a maximum Modified relation, and the contact cannot be intru­ Mercalli intensity of V or greater that sive because of the age relationship of the are known to have occurred since 1833.

rocks, the absence of meblmorphism, and Figure 1 shows the locations1 where possi­ the lack of veins and dikes in the sedi­ ble, of the earthquakes listed in Table 1. mentary strata. They concluded that only The four largest earthquakes in the Puget a major fault could explain the observed Sound area since 1833 occurred in 1939, field relations. (2) Fault breccia and 1946, 1949, and 1965. The largest known slickensides were found at several loca­ earthquake in the history of the State oc­ tions discussed in detail by the authors. curred on April 13, 1949. The epicenter Geologic mapping in western Washington was located between Olympia and Tacoma and particularly in the Puget Sound area along the southern edge of Puget Sound. is extremely difficult because of the wide­ The maximum Modified Mercalli intensity spread cover of glacial material. Conse­ was VIII and the magnitude wa.s 7.1 quently, the nature of :faulting is difficult (Murphy and Ulrich, 1951). The spatial to establish and much of it is unknown -at relationship between the April 13, 1949 the present time. and the April 29, 1965 shock is shown in Figure 1. Eight people were killed in the SEISMICITY 1949 earthquake and many injured. Prop­ erty damage in Seattle, Tacoma and The Puget Sound region is part of a Olympia was approximately $25,000,000. moderately active zorie of seismicity ex­ The earthquake was felt over an area of tending from the vicinity of Portland, 150,000 square miles. The seismological Oregon north through Puget Sound to aspects of the 1949 earthquake have been the Canadian border and Vancouver Is­ discussed by N uttli ( 1952). land. The first earthqualr·- listed by The November 12, 1939 earthquake with Townley and Allen (1939) in .'·~ir cata­ a maximum intensity of VII and a mag­ logue of Washington earthquakes oc­ nitude · of 5% was felt over an area of curred on June 29, 1833 in Thurston 60,000 square miles in the United States. County, near the southern end of Puget The felt area in Canada could not be com­ Sound. The same authors state that their listing is practically complete for moder­ pletely determined. Earthquake damage ate shocks perceptible over areas of 50,000 was confined to fallen and twisted chim­ square miles for that portion of the State neys, cracked masonry, concrete and plas­ lying west of the Cascade Range. Heck ter (Bodle, 1941). No structural collapse and Eppley (1958) and records of the of buildings was reported. The most Coast and Geodetic Survey since 1958 list severe damage was in Centralia, Elma and 113 earthquakes with a Modified Mercalli Olympia. Coombs and Barksdale (1942) intensity of V or greater in Washington have discussed the macroseismic effects of from 1841 through April 1965. The the earthquake in some detail. f778-888~ 43

4 COAST AND GEODETIC SURVEY The epicenter of the February 14, 1946 few deaths were charged indirectly to the earthquake was 18 miles north of Olympia shocks, and damage was estimated at $250,- and about 7 miles northeast of the 1949 000, most of it occurring in Seattle. The shock. The magnitude was 534 and the depth of focus was estimated at 25 km or maximum reported intensity was VII. more (Bodle and Murphy, 1948). Felt The felt area was 70,000 square miles. A aftershocks occurred 20 to 30 seconds af-

122°

•

+ 47°30' • '

INTENSITY {M.M.)

• VIII • VI

e VII e V 10 0 10 20 30 HAH HHI 1 123° Kilometers

Figure 1.- Earthquakea in the Puget Sound, Washington. area, 1833-A.pril 1965. 44

THE P UGET SOUND, WASHINGT ON EARTHQUAKE 5

TABLE 1.- Earthquakes in the Puget Sound Area, 1833-April 1965

Year Date Pacific Stand· N W Depth Area Intensity Magnitude Authority.. ard Time Latitude Longitude M.M.

h m deg. deg. km. aq. ml. 1859 Apr. 2...... 02 30 ....•.••.••• ··········- ..••••.••.•...... ••••• V ...... ••...•....••.. 1872 Dec. H-16.... ••• ••••.• .••• ••••.. •• •••• •• •••• •...... • . •• • • ••••...... 160, 000 VI. •••••••...... •••.. . 1880 Dec. 12.... . •... . 20 40 •••••••••.••.••••••••••• •••···•••••• ••••••. ....• VI••••....•••••• . ...•• 1886 Oct. 9...... 08 00 47 123. o .•.•.••..•...... •.• VI. . . . . •••••••••••.••• 1885 Dec. 8.... ••••••• 22 40 47. 5 122. ~ .•••••••...... V . .•..••••••..•.•••••• 1903 Mar. 18. ••• ••.•.• 18 15 47. 7 122. 2 •••••...... 10,000 V •.••••••• ...... •..... 1913 Dec. 25... . •. .... 06 40 47. 7 122. 5 ••...... •.•• 8, ooo v ...... 1914 Sept. 5...... 01 35 47 123 •...... •..•. 1,000 V •••••.. ..••••.•...••• 1916 Jan. 1...... 16 62 47. 3 122. 3 ...••••••••. 12,000 V .•...... • •••••••.•••• 1931 Dec. 31.. . . ••••.. 00 25 47. 5 123. 0 .•.•.•.••••. 10,000 VI. . . . ••.••••...•••.•. 1932 Aug. 6... ..••.•.. 14 16 47. 7 122. 8 .•••••.••. . . 500 VI.. ..•••••.....••.... 1938 Jan. 6...... 05 11 47. 8 122. 4 •••...... •••••••••. .. V ••••••...... •.. ..•• 1939 Nov. 12...... •23 45 54 47.2 123.0 •...... •• 60.000 VII...... 5.8 1944 Mar. 31. . .•...... 14 16 47 123 . ...•••.•••. 2. 500 V ••...... ••••••••••••• 1946 Feb. U . ... . •.... •19 17 47 t7. 3 122. 9 ••••••••. .•. 70,000 VII...... 5. 8 1949 Apr. 13...... ••.. ·11 65 41 47. 1 122. 7 ...... 160,000 VIIT...... 7.1 19M May 4_...... • 17 42 29 47. 3 122. 4 .•.••••. .•.. 1,500 V.. . •..•••...... •• 1954 May 15...... •05 02 13 47. 4 122. 3 ••• .••...... 17,000 Vl. ••.•...•••.•••. •••• 1966 Jan. 6...... '20 ao 3~ 4'.3 122.4 ••••...... •• 2,500 V .••••.....•••.••••••• 1 1957 May 4...... *13 09 27.2 4;,4 122. 4 40 2,000 V...... ••••••..•..... 2.3 1960 Apr. 10.. •• •••••• •22 47 35 47. 6 112. 3 •••••...... • 600 VI. •..•.•...... •••• 2 1963 Jan. 24...... •13 43 11.8 47. 4 122. 1 17 5. 500 Vl. . ••.. .. ••••••••.•.. 2 1004 Oct. 16 •.. ..•• -.. •os 32 37. 6 47. 7 122. 1 33 ••••••.•••.. v ...... 4 1966 Apr. 29...... •oo 28 43.6 47. 4 122. 3 59 130,000 VII...... 6.. ~ 4

• Instrumental epicenters. •• Authorities are as toUowa: l. Heck, N. H. and R. A. Eppley, Earlho®kt Hlalorv of the UnUtd State,, Part 1: Oontlnental United Staua and Alaaka, U.S. Department of Commerce, Coast and Geodetic Survey Report No. 41-1, 1958. Z, UnUt

TABLE 2.-Summarg of Hypocenter Computations

llypocenter Origin Tims N w No. or Average Computation G.M.T. Latitude Longitude Depth Stations Residual• Comments No.

h m J deg. deg. km . JU. ! ...... 16 28 43.6 47. 4 122. 3 59 120 1.1 Depth lree. 2••••••••••••. . . 15 28 43.6 47.3 122.2 60 80 1.0 Depth fixed at 60 Ian; station, with o>25" only. 3 ••••...... •••• 15 28 43.5 47. 4 122.4 60 25 0.9 Station distributed approximately equally In azimuth; depth fixed at 60km. 15 28 43. 6 47. 4 122.4 61 25 0.9 Station distributed azimuth; •··············· depth rree.

• As used In this table, the average residual Is dellned by the equation

2: I o- c I Average Residual Number or Stations 45

6 COAST AND GEODETIC SURVEY ter the main shock and the following morn­ depth of focus was not constrained. Sta­ ing at 4 :18 a.m. (Barksdale and Coombs, tions located at distances greater than 25° 1946). were used in the second hypocenter com­ In July 1949, modern seismic instrumen­ putation in order to eliminate the effects tation was installed in Seattle and a much of velocity and crustal layering variations clearer picture of local seismicity emerged. in the crust and upper mantle on hypo­ During 1950, the Seattle station recorded central location. The focal depth was con­ 77 earthquakes with epicentral distances strained to 60 km since there is practically of 7° or less from Seattle (Vesanen and no focal depth resolution possible when Jones, 1951). Thirty-nine of these all the data are recorded at distances shocks were within a distance of 1 ° from grenter than 25°. Twenty-five stations Seattle. Neumann (1959) discussed the grouped to provide as nearly as possible instrumental location of earthquakes in uniform coverage in azimuth were used the Puget Sound area from 1951 to 1957, in the fourth hypocenter computation. developed travel times, and studied the Table 2 is a summary of these hypocenter crustal layering and velocity distribution. computations. Table 3 shows the travel Perhaps the most remarkable feature of time residuals for the four hypocenter cal­ the seismicity of Puget Sound and vicinity culations summarized in Table 2. Figures is the increase in seismic activity within 8, 4 and 5 show graphically some of the the last quarter century. With the pos­ residual data contained in Table 3. Ex­ sible exception of a shock in 1872, no earth­ amination of Table 2 shows that for the quake with a reported intensity greater three data sets used, there is a variation than VI has been kno,vn to occur between of only .1 ° in latitude and .2° in longitude 1888 and 1989. From 1939 through April among the epicenters computed. For the 1965, three earthquakes of intensity VII two data sets in which the depth was com­ and one of intensity VIII occurred within puted, the variation in depth of focus is an area of approximately 800 square miles. only 2 km. The calculation using 60 sta­ Several authors (Heiskanen, 1951 ; tions at distances greater than 25° prob­ Bodle and Murphy, 1948) have remarked ably displaces the epicenter eastward for on the large gravity anomaly associated the following reasons : First, the crustal with Puget Sound. The epicenters of all velocity is, on the average, lower than it four large earthquakes that have occurred is to the west of the epicenter and second in the last 26 years are located on the there were more stations used that a.re east flanks of rather large Bouguer anomalies of the epicenter than west of it. The cal­ as shown on the Bouguer Gravity Map of culation using stations distributed as the United States (1964). equally as possible in azimuth may be sig­ nificant. Unfortunately, only a rather HYPOCENTER, ORIGIN TIME AND small number of stations are available for MAGNITUDE this type of ca1cu1ation. The depth of The dig-ital computer program described focus is believed to be well determined, by Engdahl and Gunst (1965) was used probably within ±10 km. Four stations for the computation of the hypocenter of were within 80 km of the epicenter and the the April 29 earthquake. Four hypocen­ largest residual among these stations was ter computations were made using various 1.2 seconds. It is concluded that the best data sets. In some cases, the depth of hypocentral location was obtained using focus was constrained to an arbitrary, but readings from 120 stations. This location reasonable value. The first computation is 47.4°N latitude and 122.8°\V longitude, used P phase arrival time from 120 sta­ focal depth, 59 km. The origin time was tions. These data were considered to be 15: 28: 43.6 G.M.T . This epicenter is the most reliable that were available. The plotted in Figure 2. 46

THE PUGET SOUND, WASHINGTON EARTHQUAKE 7

TABLE 3.-Summarg of Travel Time Reaiduau for Four Hgpocenter Computation&

Ob6erved-Jeffreys-Bullen Travel Time Residuals Station Phase Distance 1• 2· a• 4•

dLo.

Beattle (Marshall) (STT) eP 0.1 1.2 0.8 o. 7 Beattle (SEA) IP 0.3 -0.1 Tumwater (TUM) JP 0.6 -0.6 0.1 0.0 Loogmlre (LON) IP 0. 7 - 0.2 --0.6 -0.7 VlclOrla (VIC) IP 1.4 -1.6 -LO -1.0 Belllocham (BLL) IP 1. 4 0.6 0.6 0.6 Corvallb (COR) IP 2.9 -2.l -1.7 -1. 7 Pentlcton (PNT) IP 2. 7 2.3 Spokane (BPO) IP 3.4 0.3 Blue Mountain (BMO) IP 4.3 0.3 Port Hardy (PRC) IP 4.8 -2.4 Butte (BUT) IP 6.8 0. 1 Fort St. James (FSJ) IP 7. 2 -0.2 Orov111e (ORV) eP 8.0 -3.6 EdmonlOn (EDM) lP 8.3 -1.8 Ukiah (UKl) IP 8.3 -1.0 Byerly (BKS) IP 9.6 0.3 Dugw1y (DUO) IP 9.9 2. 4 Salt Lake City (SLC) IP 10.0 2. 4 Unlta Basin (UBO) IP 11.6 1.9 Woody (WOY) IP 11. 9 -0.3 Kloc Ranch (ltRC) eP 12.2 0.8 Sitka (SIT) IP 12.6 2.0 Boulder City (BCN) IP 12. 7 -0.0 OoldslOne (0SC) IP 12. 7 0.1 Pasadena (PAS) IP 13.6 2.1 Riverside (RVR) IP 13.9 1.2 Golden (OOL) IP 1'.6 I.I Tonto Forest (TFO) eP IU 1.8 u u Albuquerque (ALQ) IP 17.2 I . I 0.6 0.6 Tucaoo (TUC) IP 17.4 1.1 0.8 0.8 Lub~lt (LUB) eP 20.7 -0.9 Copper Mine (CMC) eP 20.9 -0.8 Anchorace (AMU) IP 21.0 1.6 2.2 2.4 L6-ce (LAW) IP 21.4 -0.8 Wichita Mountain (WMO) eP 21 .8 -1.0 College (COL) 11' 22.3 0.3 Tulsa (TUL) IP 22.8 - 0.2 Fayettevllle (FAY) IP 28. 7 -0.1 Chicago (OHK) IP 26.2 -0.1 Oxford (OXF) eP 27.8 -1. 7 -0.8 Barrow (BRW) lP 28.9 -1.0 -1.8 --0.6 --0.6 Mould Bay (MBC) IP 29.0 0.1 - 0.3 Cleveland (CLE) IP 29. 6 -2.8 -1.6 Cumberland Plateau (CPO) eP 29. 7 -2.7 -1.9 Resolute (RES) eP 29.8 -0.8 -1.0 MorpnlOwn (MRO) IP 81.4 -2. 1 .- 1.3 Ottawa (OTT) IP 31.8 -2.8 -2.2 Atla.nta (ATL) lP 31.8 -1.2 -0. 4 - 1.6 -1.6 State College (SCP) IP 32.2 -2.4 -1.7 Blacksburg (BLA) IP 32.8 -1.0 -0.2 Frobbher Bay (FBC) eP 33.4 -2.4 -2.2 Georgetown (OEO) IP 33. 7 -2.1 - 1.4 Columbla (CBC) IP 33.e -0.6 0.3 Chapel Hill (OHC) IP 33.9 -1.8 -1.1 Phl.ladelphla (PHI) IP 84. 6 -0. 4 0.8 Pallaades (PAL) IP 34.8 -2.6 -1.9 Adak (AD-) eP 84.8 -1.9 -2.6 -I. I -1.0 Fordham (FOR) IP 84.9 -0.3 0.4 ·······-··-· •••••••••..... Hawallan Volcanic ObeervalOry (HVO) lP 38. 7 0.6 0.4 1.2 1.3 lClpapa (KIP) eP 38. 7 0.8 0.6 Honolulu (HON) IP 38.8 o.e 0.4 1.4 I. 6 Oodhavu (ODB) IP 39.4 0.2 0.3 Bermuda (BEO) lP 46. 7 -1.1 - 0.6 Kap Tobin (ltTO) IP t9.6 0.6 0.4 Altureyrl (AKU) IE 63.2 o. 7 0.8 See rootnote at end or table. 47

8 COAST AND GEODETIC SURVEY TABLE 3.-Summarg of Travel Time Residuals for Four Hgpocenter Computations-Continued

Observed-Jeffreys-Bullen Travel Time Residuals Station Phase llist.ance l ' 2' 3' 4'

dtg.

San Juan ($JO) IP M.l -0.1 0.6 ...... Chlnchlna (CHN) eP 58.2 1.0 1.8 ------Caracas (CAR) iP &9.2 -1.l - 0.3 -1.3 -1.2 Bogota (BOO) IP 59.3 0.6 1. 3 0. 4 0.6 Tromsoe (TRO) IP 59.9 - 0.6 -0.8 ·------···········-·· Kevo (KEV) IP 61.0 -0.2 -0.3 ------KJruna (KIR) IP 61. 7 -1.2 -1.3 ---·-········· ...... Trinidad (TRN) IP 62.6 -3.3 - 2.6 ·------·- --·--·-······- Sodanlcyla (SOD) eP 63.2 -1.4 -1.5 ------·-- -·-·------···- Valentia (VAL) IP 65.3 -0.4 -0.2 Llllehammer ------······- ·--·-··------(LHN) IP 65. 5 0.2 0.2 ...... _...... Eskdalemulr (ESK) IP 65.6 -0.2 -0.1 ...... Kongsberg (KON) IP 66.3 0.3 0.3 0.3 0.6 Ponta Delgada (PDA) IP 67.4 0.5 0.8 0.3 0.4 Uppaala (UPP) lP 68.2 -0.6 -0.7 ------Papeete (PPT) IP 69.1 - 0.8 -0.5 - 0.3 - 0.2 Nunn!Jarvl (NUR) IP 69.2 - 0.3 -0. 4 ...... Matsusblro (MAT) IP 60.8 -1.8 -2.2 -1.2 -1.0 Copenhagen (COP) eP 10.6 1., 1.5 ----·-·--·--·· ...... Nana (NNA) lP 71.6 0.2 0.8 ...... ----··------Uccle (UCC) eP 72.0 2.0 2.0 --·-----······ ·-·--·-·-·---- Huancayo (HUA) IP 12., 1.8 2...... Warml!ontalne (WRM) eP 73.2 2. 7 2. 8 ...... Porto (PTO) lP 74-1 1.1 1.3 ·--·------·----····· Collmberg (CLL) lP 14.6 1. 0 1.0 ------··-····- ---·------·· Moxa (MOX) lP 74-6 0.2 0.3 ...... A11amalu (AFI) IP 75.3 -0.7 - 0.7 -0.1 0.0 Strasbourg (STR) IP 75.1 1.6 1. 7 ------·----- Pruhootce (PRU) IP 76.1 0. 7 0. 7 ...... -··-----··-··- Toledo (TOL) IP 77.2 1.6 1. 7 ...... ------·-··--·- Arequipa (ARE) IP 78.1 1.4 2.1 ...... - ...... Isola (ISO) IP 78.6 1., 1.6 ···-·--·-·---- ...... Trlesta (TRU IP 79.6 0.8 0.8 ···-·------·-···--··- La Paz (LPB) IP 80.0 - 0.2 o., -0.8 -0.2 Ifrane (IFR) eP 81. 7 -0. 4 -0.2 - 0.5 -o.• Ouam (OUA) eP 82. 0 -1.9 -2.2 -1.3 -1.2 Rome (ROM) eP 82. 6 - 0.5 -0. 4 --·------·-· ...... ____ Beograd (BEO) IP 82. 6 2.4 2.6 ...... Istanbul (1ST) IP 88.. 0.6 0.6 ...... Honiara (HNR) eP 88. 7 1.0 0.9 ...... Kast.amonu (KAS) IP 89.1 2., 2., ------·-··-····-- Rabaul (RAB) IP 80.0 -Z.2 -2.3 -----·--·------··--- Hong Kong (HKC) IP 94-1 0.3 0.0 ...... __ --·---·-----·- Baguio City (BAO) IP 95.2 -0.4 - 0.6 ...... Manila (MAN) eP 96.3 0.9 o. 7 -----··-···-·· ...... _ Port Moresby (PMO) IP 117. 2 - 0.5 -0.7 ------·----- . -··---·-····- Teheran (TEH) IP 117. 1 2. 1 2. 0 ·------··--- ·----····--·- Warsak (WRS) eP 117.9 -0.1 - 0.3 ...... ····---·-·--·- Jerusalem (JER) IP 98. 7 1. 6 1.6 ·-----·--······ ·-----·--·--·- Labore (LAH) eP 100.0 0.2 0.0 ------··--· ...... Sblllong (SHL) IP 101.1 0.4 -0.6 ------·--·--·-----·· Quetta (QUE) eP lO'l. 4 0.6 0.4 -··--··--··-·----·----·····- Sblra1 (SHI) eP J03.2 0.9 0.8 ...... ·------·- Wellington (WEL) eP 104. 4 0.4 0.6 ··----·------··-··-····-

' Numbers refer to the hypocenter computation numbers of Tabl9 2. 48

THE PUGET SOUND, WASHINGTON EARTHQUAKE 9

122°

+ 47°30'

APRIL 29, 1965

•APRIL 7, 1965

Tumwater Main Shock (April 29, 1965) •• Possible For~shock • Permanent Seismograph Stations

10 0 10 20 30

Kilometers 123°

Fig1tre 2.-Locatio-n map of the epicentral area showing permanent seismograph, stations, epicenter of the .4.priZ 29 earthquake and a possible foreshock on April i, 1965. 49

10 COAST AND GEODETIC SURVEY

+3 , •• • ouc •• +2 . • • . s,r • . • • • • AMU • q- • COP.. • • Q. t i • • •• :LO• . ..., • ., • • < • . • 8M0 8KS •• COL •• => M8C ,. • 9 u • . .. .. • . • w 0 . . "'w ~ ••• • .. , • ,· O< • • •• • l;N • TUM • • w ••• • • ~ ••• • • • ;:: - 1 • •• .• •• . • a.. • • GUA •• . • MAT -2 COR • • • • • • • • • . - 3 AO 80 120 160 200 2•0 280 320 360 AZIMUTH (DEG)

Figure 8.-Residual distrilmtion with azim1tth for 120 station hvpocenter solutions. depth not ccmstrained.

+3

DUG • • . -+ 2 • ,· A.M.U • e . ... . u • AlO cop• • Q. +I • • • ..., - • • BOG ' • • < • COL • . • • • => - . • MSC • • ov ••• . ~ • -w 0 • • . ' ••• ~!a. , , • .. ..• , .... • ' •' ' ""w ... ' ruM • • • ~ _, • • • •AFI ;:: •• -. • .. 0. • • • . • \ . - 2 MAJ • • .. • • •• • •. • -3 10 20 30 AO 50 60 70 80 90 100 110

DISTANCE (DEG)

Figure 4.-Residual distribution with distance for 120 station hypocenter solutwns, de1>th not constrained. 50

THE PUGET SOUND, WASHINGTON EARTHQUAKE 11

•3 AMU• •2 Ci •• i +I ALO • < • $0G • • ::> KON• . 0 AZIMUTH (DEG) ru... ;;; 8"o w !!?. 40 . 80 • 160 • 240 280 320 360 "'w • • LON ~ ;:: -1 .. • ... • . -T • • -2 COR

03

Figure 5.-ReaiduaZ distribution with azimuth for ZS station hypocenter solutions, depth not constrained.

The body wave magnitude (mb) as com­ INTENSITY .puted routinely by the Coast and Geodetic The April 29 earthquake was felt over Survey was 6.5. This magnitude is cor­ 130,000 square miles, a felt area exceed1>,d rected for a focal depth of 59 km using the only by the 1949 earthquake in the same charts published by Gutenberg and vicinity. The Modified Mercalli intensity Richter (1956). A surface wave ma()'ni- c map of the April 29 earthquake is shown tude (M.) was also computed using the in Figure 6. This map was prepared from ~omp_uted horizontal ground amplitude, reports of Coast and Geodetic Survey in­ m rrucrons, of the maximum amplitude vestigators who visited the areas of great­ surface wave with periods near 20 seconds est damage and from an analysis of 584 recorded on a horizontal seismometer. In earthquake intensity questionnaire cards practice, the amplitudes determined from returned to the Coast and Geodetic Sur­ each horizontal seismometer are combined vey by voluntary cooperators. The inten­ vectorially. No depth correction was ap­ sity cards are based on the Modified Mer­ plied to the surface wave magnitude. The magnitude results are summarized in calli Intensity Sea.le. Table 4. No station corrections were ap­ The earthquake was characterized by a plied to any of the magnitude calculations. relatively large intensity VII area and small pockets of intensity VIII damage TABLE 4.-Magnitude Calculations in Seattle and surrounding suburbs. Ex­ tensive damage to chimneys was noted in Station Distance fflb M, ---- West Seattle. The number of damaged chimneys in 188 city blocks of West Seat­ dtg. Oodbavu (ODH) 39. 4 6.1 6.6 tle were counted. It was found that 1,712 Quito (QUI) 60. 2 6.8 6.5 Valentia (VAL) 64.1 6. 7 6. 8 chimneys of the 5,005 in this area were Eslcdalemulr (ESK) 64.6 6.5 6. 4 damaged. The results of this damage Ponta Delgada (PDA) 67. 4 (') 6.9 Copenhagen (COP) 69.4 6.4 6.5 survey are shown in Figure 7. The ratio Athens University (ATU) 86.6 6. 2 6.2 of damaged chimneys to the total number Avera&e 6.5 6.5 in each block has been plotted for each 'No short period selsmograms. block surveyed. Since the city blocks in

778-88&~ 51

12 COAST AND GEODETIC SURVEY

1220 1200 11a• ' 116°

'<"-. __

0 t_ T C O L U M B A ''l'" \ \

5~ \

• limits of Felt Area { • • Penticton • • 0 •

• ,a•

(1 D E ti D 1200 O ".:' 11e• C

D MODIFIED MERCAlll INTENSITY MAP 0 co Puget Sound, Washin.gton Earthquake 0 C

April 29, 196S l·IV • VI • vm ® V VD * • STATUTE MILES 100 150 200 0 ~ .lO ,., .lO 200 122° 0 116°

Figure 6.-lntensity map of the Puget Sound, W ashington earthquake of April 29, 1965.

this area are rectangles of approximately ti ve of the damn.ge in the area. The rela­ the same size, the ratio of damaged to tion of this observed damage to the local total number of chimneys is representa- geology, particularly the distribution and 52

THE PUGET SOUND, WASHINGTON EARTHQUAKE 13

sound

4 4 4 4 I 48440364 2 555344) 6 4 5 5 5 3 4 4 68565747 4 WAY 5 5 3 3 S 3 5 5 3 3 6 6 8 710

4 6 5 No Oo,o 76 6676475445 6 7 7954568563 332 8532124440 2111121212243 No Do,o 5 02122323766

2

No Doto ~

~ >- ~~ ...; < )' > ~ ~ -¥ < w ~<; >- I~ <., '<,; 0 w C "'w > a<..., ..., < w ... :x: C :::,z .,,... M ~ No Doto i 3 .,;

Plotted Number X 10- 1= Rotio of domoged

chimneys to total number of chimneys

per block

, oo."'o....,._.o<=='=ioo... oa;;aaa;...:= :=::3'5000~,.,;·,,.,:· .1290 r •P 0 S I KtlOMEIER 111° 25' &idF3F-i- J

F-igure "/.-Map of West Seattle showing the damage to chimneys in the area. lithology of the underlying glacial de­ pockets of high intensity which might be posits, is presently under study. In addi­ considered as fitting marginally into the tion to the extensive chimney damage in Modified Mercalli VIII intensity were West Seattle, two schools were consider­ Harbor Island in South Seattle and Issa­ ably damaged. Slumping was observed quah, about 15 miles east 0£ Seattle. A along a steep slope adjacent to 36th Ave­ brick garage partially collapsed and one nue S.W. near Admiral Way. Other school was extensively damaged in Issa- 53

14 COAST AND GEODETIC SURVEY quah. There was also considerable dam­ Beach, Coupeville, Darrington, Dryden, age to chimneys in this area. Damage in Dupont, Easton, Elbe, Everett, Fall City, the Harbor Island area of Seattle and Fort Steilacoom, Fox Island, Frances, the other observed vibration damage are Gate, Gig Harbor, Gooseprairie, Graham, discussed in detail in the engineering por­ Granite Falls, Grotto, Hadlock, Harper, tion of this report. Hobart, Index, Kapowsin, Kent, Kosmos, Although intensity VIII damage was La Center, Lakebay, Lake Stevens, Lake­ observed in a few areas, this earthquake wood, Langley, Leavenworth, Leba.m, Lil­ is best described, in terms of intensity, as liwaup, Longview, Lyman, Maple Falls, an earthquake with maximum intensity Marblemount, McKenna, Medina, Menlo, near the upper limit of intensity VII. Mercer Island, Midway, Mineral, Monroe, Observed intensity VIII effects are diffi­ Montesano, Morton, Mossyrock, Mukilteo, cult to evaluate because many of the build~ Napavine, Nooksack, Nordland, Omak, ings in these areas were damaged in Palmer, Pe Ell, Peshastin, Portage, Por­ previous earthquakes, notably in 1949. ter, Port Gamble, Port Ludlow, Poulsbo, Tho following list summarizes the locali­ Rainier, Raymond, Redmond, Renton, ties experiencing a given intensity of V Rochester, Rollingbay, Roslyn, Roy, Sat­ or greater during the earthquake. For sop, Selah, Selleck, Shelton, Silverdale, reference, an abridged version of the Mod­ South Bend, Southworth, Stanwood, ified Mercalli Intensity Scale of 1931 Suquamish, Tahuya, Tokeland, Toutle, (Wood and Neumann, 1931) with equiva­ Tukwila, Union, Vader, Vashon Island, lent intensities according to the Rossi­ Vaughn, Woodinville. Forel Scale is given following the list of INTENSITY V intensity data. Acme, Ajlune, Aloha, Amboy, Anderson WASHINGTON Island, Baring, Bay Center, Beaver, Belle­ vue, Blaine, Blanchard, Bow, Brewster, INTENSITY Vlll Bridgeport, Burien, Bush Prairie, Carls­ Issaquah, Seattle. borg, Castle Rock, Chelan, Chewelah, INTENSITY VII Clearlake, Colfax, Copalis Crossing, Cos­ Allyn, Black Diamond, Buckley, Car­ mopolis, Cougar, Cowiche, Curtis, Custer, nation, Cumberland, Dash Point, Des Deep River, Doty, Eastsound, Edmonds, Moines, Dockton, Duvall, Eatonville, Ellensburg, Elma, Everett, Ferndale, Electron, Enumclaw, Ethel, Gold Bar, Freeland, Galvin, Gardiner, Glenoma., Gorst, Grapeview, Kenmore, Kingston, La Glenwood, Grayland, Grays River, Ham­ Grande, Lakeview, Longbranch, Man­ ilton, Heisson, Hoodsport, Humptulips, chester, Maple Valley, McCleary, Milton, Ilwaco, Inchelium, Indianola, Joyce, Kel­ North Bend, Oakville, Olalla, Olympia, ler, Keyport, Kittitas, Lacy, La Conner, Orting, Port Orchard, Preston, Puyallup, Lakewood, La Push, Littlerock, Long Quilcene, Ravensdale, Retsil, Ronald, Beach, Loon Lake, Lopez, Lynden, Lynn­ Seattle, Skykomish, Snoqualmie, Snoqual­ wood, Malaga, Malone, Marysville, Mat­ mie Falls, South Colby, Sultan, Tacoma, lock, Mazama, Methow, Monitor, Moxee Tumwater, Wauna. City, Naches, Nahcotta, Neah Bay, Neil­

INTENSITY VI ton, Oak Harbor, Onalask~, Orondo, Oy­ Adna, Amanda Park, Ardenvoir, Ar­ sterville, Pacific Beach, Packwood, Port lington, Auburn, Beaver, Belfair, Bothell, Angeles, Potlatch, Pullman, Randle, Bremerton, Bridgeport, Brinnon, Brook­ Redondo, Richmond Beach, Rock Island, lyn, Bucoda, Burley, Burlington, Carbo­ Ryderwood, Senbeck, Seahurst, Se.a.view, nado, Cashmere, Cathlamet, Centralia, Sekiu, Silvana, Silver Creek, Silverlake, Chehalis, Chelan Falls, Cinebar, Clallam Skamokawa, South Cle Elum, South Bay, Clinton, Concrete, Conway, Copalis Prairie, Startup, Sumner, Swift Dam, 54

THE PUGET SOUND, WASHINGTON EARTHQUAKE 15 Tenino, Thorp, Toledo, Tracyton, Wal­ noticeably. (IV to V Rossi-Forel dron, Wilkeson, Winlock, Yakima, Yelm, scale.) V. Felt by nearly everyone, many awakened. Zenith, Zillah. Some dishes, windows, etc., broken; a OREGON few instances of cracked plaster ; un­ stable objects overturned. Disturb­ INTENSITY VI ances of trees, Poles, and other tall Astoria, Clatskanie, Fort Stevens, New­ objects sometimes noticed. Pendulum berg, Seaside, Wauna. clocks may stop. (V to VI Rossi-Fore! scale.) INTENSITY V VI. Felt by all, many frightened and run out· Beaverton, Buxton, Cannon Beach, doors. Some heavy furniture moved; a few instances of fallen plaster or dam­ Cornelius, Dee, Fairview, Gales Creek, aged chimneys. Damage slight. (VI Gresham, Hubbard, Idanha, McMinnville, to VII Rossi-Fore! scale.) Netarts, Philomath, Portland, Sandy, VII. Everybody runs outdoors. Damage neg­ ligible in buildings of good design a.nd Scappoose, Tidewater, Timber, Tygh Val­ construction ; slight to moderate In ley, Valsetz, Warrenton, Wemme, "\V"il­ well-built ordinary structures; consid­ lamina. erable in pQorly built or badly designed structures ; some chimneys broken. No­ BRITISH COLUMBIA ticed by persons driving motorcars. INTENSITY VI ( VIII Rossi-Fore! scale.) VIII. Damage slight in specially designed struc­ Victoria. tures; considerable in ordinary sub­ INTENSITY V stantial buildings with partial collapse; Grand Forks. great in pQorly built structures. Panel walls thrown out of frame struct\lres. Fall of chimneys, factory stacks, col­ MODIFIED MERCALLI INTENSITY umns, monuments, walls. Heavy fur­ SCALE OF 1931 niture overturned. Sand and mud ejected in small amounts. Changes in All intensities used by the Coast and well water. Persons driving motorcars Geodetic Survey refer to the Modified Mer­ disturbed. (VIII+ to IX- Rossl­ calli Intensity Scale of 1931. The Forel scale.) abridged version of this scale is given here IX. Damage considerable in specially de­ signed structures; well-designed frame with equivalent intensities according to structures thrown out of plumb; great the Rossi-Forel scale. in substantial buildings, with partial collapse. Buildings shifted off founda­ (ABRIDGED) tions. Ground cracked conspicuously. I. Not felt except by a very few under spe· Underground pipes broken. (IX+ cially favorable circumstances. {I Rossi-Fore! scale.) Rossi-Forel scale.) X. Some well-built wooden structures de­ II. Felt only by a few persons at rest, espe­ stroyed ; most masonry and frame struc­ cially on upper floors of buildings. tures destroyed with foundations; Delicately suspended objects may ground badly cracked. Ralls bent. swing. {I to II Rossi-Fore! scale.) Landslides considerable from river· III. iFelt quite noticeably indoors, especially banks and steep slopes. Sb1fted sand on upper floors of building, but manr and mud. Water splashed (slopped) people do not recognize it as an earth­ over banks. (X Rossi-Fore! scale.) quake. Standing motorcars may rock XI. Few, if any, (masonry) structures re­ slightly. Vibration like passing of main standing. Bridges destroyed. truck. Duration estimated. ( III Broad fissures In ground. Underground Rossi-Forel sc.ale.) pipelines completely out of service. IV. During the day felt indoors by many, out· Earth slumps and land slips in soft doors by few. At night some awak­ ground. Rails bent greatly. ened. Dishes, windows, doors dis­ XII. Damage total. Waves seen on ground turbed; walls make creaking sound. surfaces. Lines of sight and level dis­ Se.nsation like heavy truck striking torted. Objects thrown upward into building. Standing motorcars rocked air. 55

16 COAST AND GEODETIC SURVEY FORESHOCKS AND graded as to relative quality in the fol­ AFTERSHOCKS lowing manner : Coast and Geodetic Survey geophysi­ A. Four or more stations used in the cists were sent to Seattle, Washington im­ solution. Average of the abso­ mediately following the April 29 earth­ lute values of the residuals was quake to survey damage, service strong less than 0.5 second. motion instruments in operation at Seat­ B. Three stations used in the solu­ tle, Tacoma, Olympia and Ross Dam, tion. Average of the absolute and to install four temporary seismo­ values of the residuals was great­ graphs in the epicentral area to record af­ er than 0.5 and less than or equal tershocks. Table 5 describes the after­ to 1.0 second. shock instrumentation and lists the coordi­ C. Three stations used in the solu­ nates of each station. All stations were tion. Average of the absolute equipped with crystal clocks and radio values of the residuals was great­ time checks were made one or more times er than 1.0 second: daily. The first temporary seismograph Figure 8 shows the epicenters of the after­ station was in operation on May 2. The shocks located through May 30, 1965. stations were located at Bremerton, Issa­ A review of the three other large earth­ quah, Seattle, Pacific and Enumclaw. quakes that have occurred in the Puget The stations at Pacific and Enumclaw Sound area in the last 26 years, that is, in were not occupied at the same time. The 1939, 1946 and 1949, shows that Puget Pacific site was used from May 3 until Sound earthquakes are not noted for after­ May 5. The equipment was then trans­ shock sequences. Four small shocks, three ferred from Pacific to Enumclaw because in the vicinity of Chelan an\i one near of the lower seismic background at Enum­ Toutle, are reported by Bodle (1941), on claw. Operation of all temporary seis­ the basis of felt data, to have occurred in mograph stations was discontinued on May the nine days following the 1939 earth­ 15. Figure 8 shows the location and the quake. Barksdale and Coombs (1946) re­ period of operation of each of the tem­ port that two aftershocks followed the porary stations. 1946 earthquake, the first, 20 to 30 seconds During the 14 days of operation of the after the main shock and the second the temporary seismograph stations, only one following morning. Bodle and Murphy aftershock was recorded at a sufficient (1948) report two small aftershocks the number of stations to permit an epicentral day after the main shock and one eight location. Twenty-seven additional after­ days after the main shock. Murphy and shocks were recorded but could not be lo­ Ulrich (1951) report only one small shock cated because of insufficient data. No near Toutle, Washington for the six month aftershocks could be located from perma­ period following the April 13, 1949, mag­ nent station data in the time period imme­ nitude 7.1 earthquake. Evidently, the diately following the earthquake up until April 29, 1965 earthquake is following the the time the temporary stations were in pattern of previous shocks in the region. operation. One aftershock on May 30 was Seismograms from the Seattle, Seattle located using permanent seismograph sta­ (Marshall), Longmire and Tumwater sta­ tion data. The foreshock and aftershocks tions were carefully examined for the were located graphically using Neumann's month preceding the April 29 earthquake (1959) travel time curves. Table 6 lists Only one possible foreshock could be lo­ all of the phases identified on seismograms cated during this period of time. The from the temporary stations and gives the epicenter of this foreshock is shown in locations of the foreshock and aftershocks Figure 2. A more comprehensive study just discussed. The epicenters w ere of seismograms recorded during the year 56

THE PUGET SOUND, WASHINGTON EARTHQUAKE 17 122°

Issaquah Moy 2-15 ~*

+ 47 °30'

Pacific Moy 3-5 * Enumclaw Moy 5-15 * MAY 30, 1965

e Main Shock (April 29, 1965) • Possible Aftershocks * Temporary Seismograph Stations

10 0 ,o 70 JO

123 ° Kilometers

Figure 8.-Locatioti of temporary seismograph station&, ep-icenter of the April 29 earthq1take and possible aftershocks.

TABLE 5.-Location and Description of Portable Seismic Equipment

Location Coordinates Seismometer Reoord.tng Magnlflcation

dtg. min. Bremerton_------122 39.5 w Portable Benloff VerticaL ·------Paper recorder: 60 mm(mln. ______16,000 47 33. 6 N Enumclaw ______122 05.8 w Johnson-Matheson Vertical.. ______Paper recorder; 60 mm/min______16,000 47 12. 7 N Issaquah ______------___ 121 69.9 w Portable Benloff Vertical ______Paper recorder; 60 mmfmJn. ______14,000 47 35.6 N Pacific. ______122 13.8 w Johnson-Matheson Vertical.. ______Paper recorder: 60 mm/min------8,000 47 16. 4 N Seattle (Marshall). ______• • 122 18.8 w Wood-Anderson N-S, E-W··--·---- 35 mm tum: 15 mm/min ______·2. 800 47 25.4 N

' When viewed through an Bx viewer. 57

18 COAST AND GEODETIC SURVEY TABLE 6.-Chronological Listings of Foreshock and Aftershock Data, April 7-Mag 30, 1965

Station Date Phase Time 0-C Phase Time Hypocenter and Qualltyf Residual Origin Time

h m • ,ec h m , Seattle...... •.•••••••••••• Apr. 7 eP 04 40 31l.8 •-5. 7 •••••••••••••••••••••••• OT 04:40:37.6 C Tumwater ••...... •• Apr. 7 eP 04 40 42.3 -0. 4 eS 04 40 52. 7 Long. 47.1° N Seattle (Marshall) ..•.•.... Apr. 7 eP 04 40 43.0 -0.4 •••••.•.•.•...... Lat. 122.6° W Longmire •••••••••••.• •••. Apr. 7 eP 04 40 48.0 +o.4 es 04 41 oo.s Issaquah •••••••••••••••••• May 3 eP 05 14 42.0 Issaquah ••.•...... •••• May 3 eP 111 39 11.3 Issaquah ••••••••••••••.... May 5 eP 01 00 12.3 Issaquah . ••••••••••••••••• May 5 eP 18 80 38.4 •••••••••• es 18 30 47.4 ••••••••••••••·•·•·• •...... •. Bremerton... .•••••.••••. ••• May 6 e 111 39 OL2 Issaquah ••....•...... • May 6 IP 19 29 05.6 Bremerton••. . •...... •• May 7 e 09 35 13.0 Issaquah ••••.. •••.••...... May 7 eP 09 35 05.8 ••.•••••.• e 09 35 09. 6 - -·················· •••••••••••• Issaquah •••••••••.•••••••• May 8 IP 00 08 37.4 Bremerton. •••••••••••••••• May 8 IP 06 03 54.5 Issaquah •••••••••••••••••• May 8 IP 06 03 68. 7 ·······-· e 06 04 11. 4 ••·••••••·•••••·•·•· ...... Issaquah •...... • May 8 eP 11 45 41.2 Issaquah .•••.....•....••.. May 8 eP 22 13 27.2 •••••••••• e 22 13 31.3 · ·····--·-········-- ····••••···· Bremerton .•••••••••••••••. May 9 eP 11 45 47.5 Bremerton•••••••••••••.••• May 9 eP 12 23 46.1 Bremerton•••••••••••••••.• May 9 eP 14 20 19. 9 Enumclaw•••••• •.•••••••• May 10 e 05 18 47.6 Enumclaw ..•.•.••••••••.• :May 10 e Oli 21 23.6 Bremerton.•...... • May 10 IP 06 34 23.4 -1.0 eS 06 34 28.0 OT 06:34:17.5 A Tumwater... .•.•..••••..•• May IO eP 06 34 24. 7 -0. 7 es 06 34 30.4 Depth (12.5-25)•• Enumclaw••...... •.••. May IO IP 06 34 28.4 -0.2 ...... ·------·------Long. 47.4° N Seattle (Marshall)•...... May 10 e 06 34 30.2 ·+s.8 IS 06 34 33.0 Lat. 122.8° w Issaquah••.. ••••••••••••.• May 10 eP 06 34 28.5 +0.2 es 06 34 41.4 Longmire ..•••••••••••••••• May IO eP 06 34 33.5 0.0 es 06 34 44.5 Enumclaw ••...... ••••• May 10 e 11 51 25.3 Issaquah•. ••. ••••••••• - .•. May IO e 13 30 21.0 Issaquah ••••.•••••.••••••• May IO e 17 68 39.0 Issaquah ••••...... May 11 e 01 46 24.3 Bremerton...... ••...... May 11 e 08 43 55.6 Enumclaw•. •••••.••.••... May 11 e 09 15 18.4 Issaquah ••... _... •...••... May 11 e 13 29 32. 7 Bremerton....•...... •.. May 11 e 17 42 15.0 Teleselsmlc Issaquah •••...... _...... May 11 eP 17 42 20.1 Teleselsmlc Enumclaw•. ••.••..•••.... May 11 eP 17 42 22.9 Teleselsmlc Bremerton.•••.•••••••••••• May 11 eP 18 19 16. I Teleselsmlc LongmJJ-e ••• ••• •••..•••••• • May 11 eP 18 19 16.4 Teleselsmlo Enumclaw.. ...•• ...... May 11 eP 18 19 21.0 Teleselsmlc Issaquah ••••••..•••.•••••• May 11 eP 18 19 21.4 Teleselsmlc Enumclaw••...... •.••• May 11 eP 19 17 86.5 Enumclaw.. •••••..••.••.. May 12 e 01 Ol OS. l Enumclaw•. ..••.••••••••. May 12 e 14 48 47.4 Issaquah ••...... •...... •• May 12 e 18 44 45. 7 Issaquah. - ·····-··--· ----· May 12 e 20 19 13. 7 Seattle (Marshall). .••..... May 30 eP 08 46 19.4 -1. o es 08 46 23. 2 OT 08:46:12.8 B Tumwater•.. .•• . ••.••.•••• May 30 iP 08 46 22.0 -0. 8 IS 08 46 31. 3 Depth (12.5-25) •• Longmire ...•.•...... ••. May 30 IP 08 46 22.4 -0. 5 IS 08 46 29. 7 Long. 47.1° N Seattle•• ..•••.••••••.•••. __ May 30 eP 08 46 30.6 ' +7. 3 •••••••••• ••••••••••• ••• Lat. 122.2° W

•Indicates station n.ot used In solution. ••vaJues enclosed In parentheses are questionable. t Quality Is assigned (A through C) as discussed In the tert. 58

THE PUGET SOUND, WASHINGTON EARTHQUAKE 19 preceding the April 29 earthquake at sta­ earthquake is somewhat shallower than tions in the Puget Sound area. is presently 0.01 R. Tumwater is the only significant underway, but the results are not yet avail­ station appreciably affected by using ex­ able. The only other earthquake located tended distance tables for a depth of focus by the Coast and Geodetic Survey in the slightly greater than the depth of focus year preceding the April 29 earthquake of the earthquake. If the extended dis­ was on October 15, 1964, 37 km northeast tance for Tumwater is computed using of the April 29, 1965 shock. tables for a shallower depth of focus, Tum­ water plots closer to the epicenter (see DIRECTION OF FAULTING Figure 9). Plotting Tumwater nearer to the epicenter makes this dilatational first · A fault plane solution was made using motion clearly inconsistent. The diame­ Byerly's (1938) extended distance tech­ ter of the larger circle can then be in­ nique. Tables developed by Hodgson creased to include Kongsberg, thereby and Storey (1954), based on the Jeffreys­ changing the dip of the A plane by Bullen travel time curves, were used to compute extended distances. The direc­ about 3°. Nuttli (1952) published a fault plane tions of first motion recorded at 76 stations solution of the April 13, 1949 earthquake. (see Table 7) were used for the solution. His solution was later modified by Hodg­ The seismograms from 55 of these stations son and Storey (1954) on the basis of ad­ were read by the authors a.nd the other 21 ditional data. Figures 11 and 12 show readings were obtained from the stations a comparison of our solution for the April that routinely report. the direction of first 29, 1965 earthquake with the solution of motion. Eight of the seventy-three first the April 13, 1949 earthquake presented motions were found to be inconsistent with by Hodgson and Storey. Hodgson and our solutions, which amounts to 11 % error. Storey selected the B plane ( strike Figure 9 is an extended distance plot in N76°W, dip 12°S) as the most plausible stereographic projection of the direction solution for the 1949 earthquake. of first-motion of the 76 stations used in It is difficult to choose the fault plane the solution. The circles represent the A for the 1965 earthquake because both and B planes found for this earthquake. planes represent faults that strike north­ The larger circle in Figure 9 represents west, the direction that is believed to be the A plane and the smaller circle the B plane. The A plane strikes N18°W and the trend of the regional structures in the area. Both planes represent dip slip fault­ dips 69°E. The B plane, restrained by the ing which is consistent with Hodgson's orthogonality criterion, strikes N53°W ( 1957) observation that the general rule of and dips 35°W. Regardless of which strike slip faulting in the circum-Pacific plane is taken as the fault plane, the fault­ does not, in general, apply between Alaska ing is predominantly dip slip. If the A and California. plane is"taken as the fault plane, the plunge Accordingly, our B plane (strike of the motion vector is 55° and strikes N53°W dip 35°W) is chosen as the most N37°E. If the B plane is taken as the reasonable choice for the fault because it fault plane, the plunge of the motion vec­ is parallel to the regional tectonic structure tor is 21 ° and strikes N108°W. Figure 10 and most nearly agrees with the strike of shows the detail of the central area of the the fault presented by Hodgson and fault plane solution. Storey (1954) for the 1949 earthquake. Hodgson and Storey's (1954) tables for The motion on the 1965 earthquake repre­ a focal depth of 0.01 of the earth's radius sents gravity faulting whereas the solution were used in computing the extended dis­ presented by Hodgson and Storey for the tances of the stations. The focus of this 1949 earthquake represents thrusting. 778--883~ 59

20 COAST AND GEODETIC SURVEY

z z< z !... s :IE :5 ..... i!S • (B t ;s -t$ ~ (B ..... 's' ::: • (B • ~ ....§ • 0 .1:i"' ~ :: ~ ~~ (B (B . .... ,. : (B :: • • ;. l ~ • ~ ~· ~. ~ (B • • .g , (B ~ ~. ... 0 • : • • ~· ...~ it• • : .. (B ~ 8 li e ~ ...,c!"' (B • " -~ ~ !.m =e • 0 ,c!.. I ....0 "'0 b. Q,

~ .s,c! (B (B ~ ~ ~ ...t"'

ioi ~ ;:! ...c:,, l'l::,

::l (B

(B ~ ~ (B =e : (B 60

THE PUGET SOUND, WASHING TON EARTHQUAKE 21

STRIKE Nl 8°W DIP 69° N • 22 •13 • 29

• COMPRESSION A DILATATION

Figure 10.-Stereouraphi-O projection. 8howing detail of the fa,ult plane soluti.

22 COAST AND GEODETIC SURVEY

122°

+ 47°30'

FAULT PLANE SOLUTIONS

PUGET SOUND REGION

A Plane

10 0 10 20 30 AR AAA I I 123° Kilometers

Figure 11.-Comparla

THE PUGET SOUND, WASHINGTON EARTHQUAKE 23

122°

Apri l 29, 1965 + 47°30'

April 13, 1949

FAULT PLANE SOLUTIONS PUGET SOUND REGION

B Plane

10 0 10 20 30 HARRAi I I 123° Kilomelers

Fig1tre 12.- 0ompariaon of fault plane aoiutitm8 of the Aprti 29, 1965 a1id .ApriZ 13, 1949 earthquakes: B plane. 63

24 COAST AND GEODETIC SURVEY

TABLE 1.-Cluuacter of Fir,t Motion

First Motion First Motion Station Station Sbort Lo111 Short Long Period Period Period Period

L Allurtyri...... •...... C• •.•••••••...... •••• 39. Klamath Falls.• ••••...•..•....•.• (D)• •...... •••••..•.•• 2. Anchorage...... • . • . • • ...... • . • D •. . . • . • . . • •••.....•.• 40. Kono11>trg...... (C)• ••• •.. (D) 3. Ann Arbor...•.....•. ••.•...... o•...... C ~- La Pai •••••....••.•.•••.•••.•.... (D)' .••••. D 4. Arequipa •.•...... •••.••..•.•... D• •...... D 42. Long:mlre ...... ••••••••••••• •••.• o •...... D 5. AUanta...... c•...... C 43. Manila...... o• 6. Athens...... D· •....•.. D 4-l Mould Bay...... •.•..•.•.•••..•.• D ' .•..••.• D 7. Baguio City...... D· •...... D 45. Mo1.0...... D• ...... 8. BeJJlngbam ••...•..••.••...... c• ...... •...... 46. New Deihl..•• ••..•••••...... •.. -...... 0 ' 9. Beqqrad...... c• ...... 47. North Reno .•...... •••••..••....•. c•...... 10. Blacksburg...... C' ••.•.... c 48. Ogdensburg...... c•...... 0 11. Boeor.a...... CD>...... c· 411. Ottawa. ••..•••..•.•.•...... ••. o•····-·· 0 12. Boulder City... •.••...... • c••....•...... ro. Osford ..••••••.•.•••.•••....•..•.• o•...... 0 13. Bozeman ...... ••...... c· ...... 51. Palisades ••...... ••...... c•...... C a. Byerly...... •••.•... . c• 52. Pentlcton ..•...••••••••••••. •••••• c• ...... C 15. Caracas...... C' ...... 0 53. Ponta Delgada.••••••••••..•..•••.••.•...... • 0 ' 16. College •••...... •.•..••...... D • •.•••••• D M. PorUand ••.. •••••••••••...... • c· ...... 11. Copenhagen...... D· 55. Port Moresby ••..•••..••••••••••• D ••••••••• o• 18. Copper Mine...... • .• ...•.• C' 56. Porto.•..••. •.•••••••••••••.•••••• o•...... ············ 19. Corvallls .• _ ...... c· ········ ...... 57. Pru.\onlce •••.••••••••...... •.•.•• o•...... 20. Dallas...... 0 ' ...... C 58. Rahaul. ••...... ••. •.•••..•..•.• (D) .••.•.• D 21. Dugway ...... 0 ' .•...... •.•••..••••• 69. Resolute.•...... •.•..•••••••.•••. -...... C 22. Edmonton ..... ••.•••••..•..•.••••• c•...... ············ 60. Salt Lake City... .•••••••••••••••• c•...... 23. Eskdalemulr...... •••...•.••..••. o• ...... C 61. Seattle .•.•...... •...... (D) •.•.•.. •••••••••••• 2". Florissant ..._ ...... C' 62. Sitka ...... (C)• ••.. •••••••••••••• 25. Fort St. James.•.•.. •...... •••• - ••...•••• C' 63. Spolotw ...... •...•...... c•...... ---········· 26. FTobl1htr Bav•.... .•.•••••••.. ...• D ' ...... M. State College ••••...••...... C' ....•...... ZI. Georgetown ....•••••••••.•••••.... 0 ' ••...... C 65. Stuttgart.•• ...... ••....•...... (D) ... ..•• D 28. Godhavn .•.•••••.••••...••••••••• c•...... 0 66. Tehtran ...... D• •••••.•.•.•••••••.•. 29. Golden ••••....•.••••....•....•••• o•...... C 67. Tokdo ••.•••••••••.•.••.•..••••.•. c•...... 30. Goldstone . •.•... . .••••.•••...... C' ••....•• C 88. TOMj)dA ...... C' ...... •...... 31. Guam...... D 69. Tucson..•.••• •.•••••••••••••••••• c•...... o 32. Belwan...... D• 70. Tuua .••••••.•••••••••...•••••••.• c•...... 33. Hong Kong..•.. •••••••••••••••... D ' ••...... •••••.... 71. Tumwater .•. ....•••••••••. . .•.•.• D ••••••••••••••.••••.• 34. Honiara...... -...... D 72. Ukiah •....•••••••••••••••••••••.• c•...... 35. I1tanbul •.•...... •.••••..•...... ••• D • ••••.••• •••••••••••• 73. UnlonDllk •••••••••••••••....••.••• c•...... 36. Kap Tobin ...••.•.•..•.•.•..•..... O• ••...... ••••••••• 74. Valentia ...... -..... c• ...... c 37. Ka,tamonu . ...••••••••••••••..••• C' ••••.... - ·········· 75. Victoria•.• .••••••••••••••••••••••• C ' ••...... ••••••••• 38. Klrkenes•. ....•••••••••••••••• -.. c•...... i6. Yellow Knife..• •••••••••••••••••• (D) •••.... C'

Itallc Is llrst motion reported by station. 'First motion used In solution. -Signal not readable. ( ) Questionable ttading. 64

THE PUGET SOUND, WASHINGTON EARTHQUAKE 25 CONCLUSIONS ing on the Structure of the Cascade Range," Bull. Seis. Soc. Amer., Vol. 24, The Puget Sound area is a part of a pp. 51-62, 1934. moderately active zone of seismicity ex­ Byerly, Perry, "The Earthquake of July tending from the vicinity of Portland, 6, 1934: Amplitudes and First Motion," Oregon to Vancouver Island. The level Bull. Seis. Soc. Amer., Vol. 28, pp. 1-13, of seismic activity in the 'Puget Sound area 1938. has greatly increased in the last quarter Coombs, H. A., "A Summary of Wash­ of a century, the most severe· shock oc­ ington Earthquakest Bull. Seis. Soc. curring on April 13, 1949. The large Am.e1·., Vol. 43, pp. 1-5, 1953. shocks in this region have been followed Coombs, H. A. and J. D. Barksdale, by a relatively small number of after­ ''The Olympia Earthquake of November shocks. The April 29, 1965 earthquake 13, 1939," Bull. Seis. Soc. Amer., Vol. 32, follows this pattern as evidenced by the pp. 1- 6, 1942. fact that aftershock activity in the month Eardley, A. J., Structural, Geology of following the earthquake was practically North America, Harper and Row, New non-existent. Consideration of the fault York, 743 pp., 1962. plane solution for the April 29, 1065 earth­ Engdahl, E. R. and R. H. Gunst, "Use quake shows that no matter which plane of a High Speed Computer for Large­ is taken as the fault plane, the fault is of Sea le Determinations of Earthquake the gravity type with northwest strike. Hypocenters," Bull. Sei..s. Soc. Ame1-., in press, 1965. ACKNOWLEDGMENTS Gutenberg, B. and C. F. Richter, "Mag­ The authors would like to ackno,v ledge nitude and Energy of Earthquakes," An­ the assistance of C. J. Langer and B. J. nali de Geofisica, Vol. 9, pp. 1-15, 1956. Morrill of the Coast and Geodetic Survey H eck, N. H. and R. A. Eppley, Earth­ in gathering intensity information, and quake History of the United States. U.S. Norman Rasmussen of the University of Department of Commerce, Coast and Geo­ Washington for his cooperation through­ detic Survey, 80 pp., 1958. out this investigation. Heiskanen, W., "On Seattle Earthquakes and Gravity Anomalies," Bull. Seis. Soc. REFERENCES Amer., Vol. 41, pp. 303-306, 1951. Barksdale, J.D. and H. A. Coombs, Hodgson, J. H., "Nature of Faulting in "The Puget Sound Earthquake of F ebru­ Large Earthquakes," Bull. GeoZ. Soc. ary 14, 1946." Bull. Seis. Soc. Amer., Vol. Ame1·., Vol. 68, pp. 611-652, 1957. 36, pp. 349-354, 1946. Hodgson, J. H., and R. S. Storey, "Di­ Bodle, R. H., United States EMth­ rection of Faulting in Some Larger Earth­ guakes 1939, U.S. Department of Com­ quakes of 1949,n Bull. Seis. Soc. Amer., merce,· Coast and Geodetic Survey, Serial Vol. 44, pp. 57- 83, 1954. No. 637, 70 pp., 1941. Liesch, Bruce A., C. E. Price and K. L. Bodle, R. H. and L. M. Murphy, Umted Walters, Geoloqy and Ground-Water Re­ States Earthquakes 194.i, U.S. Department sources of Northwestern Kinq Oownty, of Commerce, Coast and Geodetic Survey, Washington, State of Washington, Divi­ Serial No. 714, 48 pp., 1948. sion of ·water Resources, Water Supply Bouguer Gravity Map of the United Bulletin No. 20, 241 pp., 1963. States, American Geophysical Union and Murphy, L. M. and F. P. Ulrich, United U.S. Geological Survey, 1964. States Earthquakes 1949, U.S. Depart­ Bradford, D. C., and A. C. Waters, ment of Commerce, Coast and Geodetic "The Tolt River Earthquake and Its Bear- Survey, Serial No. 748, 64 pp., 1951. 65

26 COAST AND GEODETIC SURVEY Neumann, Frank, "Crustal Structure in Townley, S. D. and N. W. Allen, "De­ the Puget Sound Area," Umon Geodesique scriptive Catalog of Earthquakes of the et Geophysi,que I nte1'1'ULtionale, Publica­ Pacific Coast of the United States 1769- tions du Bureau Central Seismologique 1928: Chapter III, Earthquakes in Wash­ International, Serie A, Travaux Scienti­ ington-1833 to 1928," Bull. Seis. Soc. fiques, Fascicule 20, pp. 153-167, 1959. Amer., Vol. 29, pp. 259-268, 1939. Nuttli, Otto W., "The Western Wash­ Vesanen, E. and J. Jones, "On Seismic­ ington Earthquake of April 13, 1949,'' ity of the State of Washington," a paper Bull. Seis. Soc. Ame1·., Vol. 42, pp. 21-28, presented at the Union Geodesique et Geo­ 1952. 'physique Internationale, Association de Poulson, E. N. and J. T. Miller, Soil Seismologie at Brussels, August 1951. Survey of King County, Washington, U.S. Wood, H. 0. and Frank Neumann, Department of Agriculture, Series 1938, "Modified Mercalli Scale of 1931," Bull. 106 pp., 1952. Seis. Soc. Amer., Vol. 21, pp. 277-283, 1931. 66

PRELIMINARY ENGINEERING REPORT

by Karl V. Steinbrugge and William K. Cloud

INTRODUCTION DESCRIP'rION AND ANALYSIS OF DAMAGE Seattle, Tacoma, Olympia. a.nd neigh­ boring cities in the State of Washington Property loss in the 1965 shock has been were damaged as the result of an earth­ estimated at $12,500,000 by the Washing­ quake which occurred at 8 :29 a.m., Pacific ton State Civil Defense Department, with Daylight Saving Time. The mb magni­ much of this loss being in Seattle and in tude as given by the Coast and Geodetic King County. Reliable sources report. Survey is 6.5, and the earthquake's epi­ $500,000 to $1,000,000 loss to the Boeing center has been placed at 13 miles south­ Company facilities and $1,500,000 damage east of downtown Seattle. The 1965 to Seattle public schools. All of these es­ earthquake had a smaller Richter magni­ timates, made so shortly after the earth­ tude than did the last major earthquake quake, are subject to considerable revision in the same area which occurred on April 13, 1949 and had a 7.1 magnitude. The as more thoroughly developed data be­ 1949 shock had its epicenter between Ta­ come available. However, in vie,v of the coma and Olympia and was therefore lo­ billions of dollars in property value in the cated somewhat southwest of the 1965 affected area, the overall property loss earthquake. from the earthquake must be considered to The damage pattern from the 1965 earth­ be slight. quake resembled that of the 1949 shock, Three persons were killed from falling with preliminary damage surveys indi­ debris, three died apparently from heart cating that the 1949 shock was the more attacks, and numerous injuries occurred. destructive of the two. Figures 13 through 19 are typical of the The focal depth of the 1965 earthquake life hazard from falling masonry. has been tentatively placed at about 36 Building damage was generally light, al­ miles. The focal depth of the 1949 shock though it was spectacular in many cases. was reported in USC&GS Serial 748 to Total collapses did not occur as far as is be "slightly greater than normal." In known to the authors. In general, dam­ view of the 10 mile focal depth commonly age patterns repeated those of the 1949 given for the majority of California. earth­ quakes, the deeper focal depth in these shock. Buildings which apparently had two shocks in Washington suggests a some­ been damaged in 1949 often sustained what more moderate surface intensity over additional damage in 1965. This reoccur­ a wider area than comparable magnitude ring earthquake damage was sometimes but shallower California earthquakes. A intermixed with pre-earthquake settlement genera.I view of the 1965 preliminary dam­ cracks which opened wider or caused fail­ age data tends to confirm this observation. ure in the 1965 earthquake. 27 67

28 COAST AND GEODETIC SURVEY

Figure 1S.-Failttre of an tmreinforcect !)rick gal)le in Seattle. The masonry fell on a parked, car, injuring occupant ( see Figure 14). ( Photo l)y Seattle Fire Department.) 0\ CX>

i-3 ~ t.%.1 ""d e c;) t.%.1 i-3 CJ] 0 dz ~ ~ >en z~ c;) i-3 0z t.%.1 ~ ~ ID d > ~ t.%.1

~ Figure 14.-Rescwing man injured in automobile due to collapse of gabie (see Figure 13). (Photo by Ken Harris, Seattle Post-Intelligencer.) co 69

30 COAST AND GEODETIC SURVEY

Figure 15.-Kin.g Street Railroad Station. in Seattle. (Photo b11 Seattle Fire Department.) 70

THE PUGET SOUND, WASIDNGTON EARTHQUAKE 31 71

32 COAST AND GEODETIC SURVEY

Figure 17.-Unreinforcecl br,ick fell from top st

THE PUGET SOUND, WASHINGTON EARTHQUAKE 33

Figure 18.-The 60-foot brick chimney at the A.Zki .EJ/.ementary School in Seattle collapsed. on the one-story boiler room, severely damaging it. (Photo by Cory Tolman, Seattle Post-Intelligencer.) 73

34 COAST AND GEODETIC SURVEY

Figure 19.-Hok in the roof d.tte to the coll4pae of the chimney shown in Figure 18. (Photo by Karl V. Steinbrugge.)

Single family dwellings in the affected tures, particularly brick veneer. Four­ areas are generally of wood frame con­ inch brick veneer peeled off of a number struction, and are rarely more than two of wood frame structures even though the stories high. Chimneys are usually brick veneer was anchored to the wood backing masonry. Interior partitions are gener­ wall with galvanized metal anchors. The ally plaster or gypsumboard on wood anchors usually remained nailed to the studs. Performance of the wool frame wood frame when the brick peeled off, and dwellings was almost always excellent, and an examination of the mortar indicated when damage occurred it was confined to that the mortar could be crushed by hand. plaster cracking and to unreinforced brick This type of veneer damage ha-s been noted chimney failure at, or above, the roof line in many previous earthquakes, and the as shown in Figures 20 and 21. By no anchorage certainly demands more careful means was the dwelling damage uniform engineering supervision than is normally throughout the city. For example, pock­ given to it. Typical veneer damage is ets of intense chimney damage to dwell­ shown in Figure 22. ings were found in Seattle ( notably in Multistory buildings generally had the West Seattle section) while nearby slight or no damage, with the damage re­ areas of similar construction had no chim­ ported to new and to old structures. Plas­ ney damage. The damage pattern would ter cracking and other non-structural sometimes change radically within sev­ damage was found in multistory buildings eral city blocks. As a rule, wood frame in Seattle as well as in Tacoma ( these dwelling damage rarely approached as cities being about 30 miles apart) . The much as 5% of building value. spectacular damage reported by the press One exception to the foregoing rule was to a 10 story building in Tacoma may have unit masonry veneered wood frame struc- been entirely confined to exterior window 74

THE PUGET SOUND, WASHINGTON EARTHQUAKE 35

Figure 20.-C'himney aamage in West Seattw. (Photo by Kari V. Steinbrugge.) 75

36 COAST AND GEODETIC SURVEY

Figure U.-Ohimney ctamage in West Seattle. (Photo by Kari V. Steinbrugge.) 76

THE PUGET SOUND, WASHINGTON EARTHQUAKE 37

Fig1tnJ 22.-Four-inch thick brief;; veneer peelecl off of this 1Nod frame atruct11re in Seattle. The ga-lvan'ized metal anchors were imbedded in a bed of 1010 strength motar. (Photo by Karl V. Steinbrugge.)

• /. • ' .,t .,•

• I ~ ""' - ,• , '

Figure 23.-Glass windows broke on three aides of th'is 10 story b·1tilding in Tacoma. The fourth side had no ioall openings. (Photo by B. J. Mon-ill.) 77

38 COAST AND GEODETIC SURVEY glass in a structure hadng essentially all moved. It was apparent when inspected glass on 3 sides, with the fourth side solid. after the 1965 shock that differential set­ (See Figure 23.) Landslide damage to tlements also had been occurring, and the a roadbed in Olympia is shown in Figure 1965 shock found a building which had 24. been weakened by both previous earth­ Unreinforced brick bearing wall build­ quake and settlement. The high apparent ings with sand-lime mortar, as usual, bore intensity at this location requires careful the brunt of the damage. This type of attention before being taken at face value. building generally has wood roofs and Modern buildings which were designed wood supported floors, and is not earth­ and constructed to be earthquake resistive quake resistive in any sense. Numerous performed well, as indeed they should in instances of parapet and gable failure oc­ a moderate earthquake. Not all modern curred, and death and injury resulted structures performed well and four ex­ from this type of damage. As previously ceptions warrant mention. A one-story mentioned, some of this could be associated warehouse, having a precast prestressed with 1949 earthquake damage as well as reinforced concrete roof and precast con­ with settlement damage which was not crete tilt-up walls with poured in place related to earthquakes. The photographs pilasters, had no anchorage between the accompanying this report are typical ex­ roof diaphragm and its end shear wall. amples of this type of damage in Seattle. The roof moved back and forth over the A classic case of cumulative damage was end shear wall, damaging the side walls. found on the mud flats of Tacoma. A two­ A second instance of damage to a building story brick bearing wall building was sig­ presumably intended to be earthquake re­ nificantly damaged in the 1949 shock and sistive occurred at a one-story market in the second story was subsequently re- which the steel angle earthquake x-bracing

Figure 24.- LancuZide damage to a roadbed in Olympia. (Photo by Karl V. Steinbrttgge. } 78

THE PUGET SOUND, WASIDNGTON EARTHQUAKE 39 was embedded in a hollow concrete block wamish River and its mouth settled and wall; the relative rigidities of the elements were the locations of considerable building were such that the hollow concrete block damage. had to fail before the steel x-bracing could Harbor Island at the mouth of the function. Additionally, the x-bracing Duwamish River was a special high dam­ was so located as to cut in two most of the age location. Much, if not all, of this wall reinforcement. A third instance of island was man-made, perhaps 50 or more note was a large manufacturing facility years ago. Some of the structural dam­ having a very large floor area; the second age to a newly built precast reinforced story precast reinforced concrete panels concrete building on Harbor Island is appeared to have worked loose from their shown in Figure 25. The soils are not seis­ supporting frame. The fourth example mically stable by any standard. On this was a four story hollow concrete block island are located a number of major in­ apartment house in which the block shat­ dustrial facilities and it is of interest to tered at several locations, and a remark­ discuss two damage examples of those able absence of vertical reinforcing steel known to haYe occurred. was noted. The mere enactment of earth­ For one example, the Fisher Flouring quake bracing laws does not automatically Mills had extensive damage to its various insure safe construction as was also shown buildings. A 50,000 gallon wood roof in the 1964 Anchorage, Alaska earthquake. tank on top of a 15-story structure fell Eight Seattle public schools, housing seven stories onto the concrete roof of a 8,800 pupils, were closed until their safety grain bin, breaking the grain bin roof and could be established. Of these schools, spilling water onto the grain. Elsewhere, the West Alki school was the most severely portions of the unreinforced brick walls hit and may not be worth repairing. Its fell from the sixth story as may be seen 60 foot brick stack fell into the boiler room in Figure 17. An examination of this (see Figures 18 and 19); x-cracks were structure showed pre-1965 cracks in the found in the unreinforced sand-lime mor­ brick walls, some of which apparently tar brickwork in the 1914 wing; stairs opened further in this earthquake. Un­ shifted; the north wall of the new wing derground piping around the plant also moved outward; however, not everything broke. Equipment in the building shifted fell from the shelves. It should be added and was out of line, and several days were that the West A1ki school was located in a required to put it back into alignment. pocket of high earthquake intensity. This plant reportedly had $50,000 damage Pockets of high earthquake intensity, as in the 1949 shock, and the damage in 1965 typified by damage such as fallen appears to be greater. chimneys, could almost always be asso­ A second instanc~ of damnge on Harbor ciated with the local geology. Damage Island occurred at Piers #15 and #16 as was the most pronounced in what is shown in Figure 26. T11ese piers shifted commonly termed "poor ground" areas. toward the water by about one foot due to These pockets were distributed over a large the soil losing much or all of its strength, region, with the areas around these pock­ or partially liquifying, and pushing the ets having damage so slight that it was dock toward the water. An exception was difficult to find it. In Seattle, a partic­ the northern extension of the pier which ularly noticeable damage pocket was the was under construction and did not yet A1ki Beach section of West Seattle where have its soil backfill. virtually every chimney was down. Re­ Fire following the earthquake was not a portedly, similar intensified damage also serious problem. In Seattle, one house occurred here in 1949. Additionally, the shifted and this shifting apparently re­ low lying and filled areas along the Du- sulted in an electrical short, with fire en- 79

40 COAST AND GEODETIC SURVEY

Figure !5.-Some of the structurai damage to a 1iewly built precast reinforced concrete building on Harbor laUl,n,d. in Seattie. (Photo by B. J. Morrill.) 80

THE PUGET SOUND, WASHINGTON EARTHQUAKE 41

Figu1·e 26.-Groun

suing. The fire alarm system remained in sulted in water supply impairment for operation. During the day the Seattle about one day to four sprinklered Fire Department had several hundred calls buildings supplied off this main. regarding loose chimneys and similar "In Everett, two of the three 48- problems. Olympia had no fires although inch main supply conduits to the city seven alarms were turned in. failed. These failures occurred where Utility damage was not severe. (See the lines are· carried on trestles over Figures 27 and 28.) An excellent sum­ Ebey Slough. Industrial supply to mary was prepared by the Washington the large consuming pulp mills was Surveying and Rating Bureau : then shut down, the mills either clos­ "Service from the various public ing down or going to rfrer pumps. utilities was, on the whole, uninter­ With the 50 m.g.d. supply from the rupted. Damage at the Spokane remaining line plus 10 m.g.d. from the Street substation of Seattle City Light 28-inch line No. l from Lake Chaplain interrupted service for a few hours in and reservoir storage, normal fire a. small area. The Washington Nat­ flows were maintained available ural Gas Company reported one minor throughout the city. Full serYice was break in the P uyallup area. The restored the following day. One Seattle Water Department had one other break was reported in a. 4-inch break in a 12-inch main in the Harbor line in a. residential district. Island area and minor breaks in small "A number of breaks occurred in pipes in residential areas of unstable underground mains on plant sites and ground. Four days after the earth­ to overhead sprinkler piping. These quake, a break in a 20-inch ma.in on were mainly to those pi;operties lo­ Western Avenue at Spring Street re- cated on artificial fills in the southern 81

42 COAST AND GEODETIC SURVEY

Figure 2'1.- Woodland Park Standpipe, Seattle. Figure 28.-Typi.cal anchor bolt damage at Typical damage to anchor bolts may be seen Woodland Park Standpipe, Seattle. Note that in next fi,g1we. (Photo by Washington Survey­ the anchor bolt has necked where it meets the ing and Ratitig Bureau.) concrete and that the bolt failed in the threads. ( Photo b11 Washing ton Sm·veying part of Seattle, particularly Harbor and Rating Bureau.) Island, resulting in varying periods of able service by conducting a building­ impairment with some not yet being by-building survey, to more accurately restored. D am age to overhead assess the extent of damage from the sprinkler piping was mainly to older quake. The effort was coordinated systems without earthquake bracing between the Fire Department, Build­ and flexible couplings. An excep­ ing Department, and representatives tion was to a number of newer systems of the U.S. Army Corps of Engineers. in buildings located on artificial fill On May 3, four days after the earth­ where suspended ceilings and light fix­ quake struck, our personnel were out tures damaged sprinkler heads and in force actually conducting this sur­ piping." vey. A damage survey of the city of Seattle "In developing the mechanics of is in its closing stages at this writing. The the program, it was decided that in following is quoted, in part, from a letter those buildings where Fire Depart­ report written by Fire Chief Gordon ment inspectors found evidence of Vickery. possible serious structural damage, the "In the day or two foll°'ving the reports would be forwarded to the earthquake, it became evident that the Building Department for re-survey by Fire Department, working in conjunc­ teams of qualified experts. tion \Yith the Building Department, "One survey was conducted on a might be in a position to render valu- continuous basis from May 3 through 82

THE PUGET SOUND, WASHINGTON EARTHQUAKE 43 May 21. During this time, a total of All six of the instruments were triggered 1,440 ma.n hours were expended, a.nd into operation by the earthquake. Copies 1,405 buildings were surveyed from of the records from Olympia, Tacoma and roof to basement. As a result of the Seattle are shown in Figures 29 through survey, 91 buildings were found to 31. have sustained apparent serious or ex­ At the time of the previous major earth­ tensive damage, and were recom­ quake in the Puget Sound area (April 13, mended to the Building Department 1949), there were strong motion instru­ for re-survey by experts as rapidly as ments only at Olympia and Seattle. Rec­ possible. One hundred and thirteen ords obtained in 1949 from these instru­ buildings were found to have sus­ ments are shown in Figures 32 and 33. tained apparent moderate damage, As the Olympia instrument was the same and were recommended for re-survey and was in the same location during both as time and personnel would permit. earthquakes, the records can be used for Two hundred and fifty buildings were comparison of the two shocks at this site. found to have sustained superficial or Figure 3-1, which shows the number of light damage only. In this group times acceleration reached various levels in there was no apparent need for a fol­ 1949 and 1965, indicates that the 1949 low-up survey, as damage consisted of shock was the stronger of the two at plaster cracks, missing chimney Olympia. bricks, and things of this nature. The Response spectra from the April 29 rec­ remaining 951 buildings were either ords are being prepared, but at this time found to have suffered no apparent only rough acceleration, displacement, and damage, or damage was so slight that period estimates based on preliminary it could not be readily recognized. scaling of records are available. These "As of this time, May 24, 1965, the data are gi,·en in Tables 8 and 9. Similar re-survey teams are approximately data for the 1949 earthquake can be found two-thirds complete with the list of 91 in the publication United States Eartli.­ buildings in the serious damage cate­ qwkes 19~. gory." ACKNOWLEDGMENTS STRONG MOTION MEASURE­ MENTS The authors would like to acknowledge the valuable field assistance given to them Within the felt area of the Puget Sound, by B. J. Morrill and by the Seattle Fire Washington earthquake of April 29, 1965, Department. personnel (Fire Chief Gordon there were six strong motion seismographs F. Vickery and Fire Marshall S. H. of the Coast and Geodetic Sur,·ey network. MacPherson) . .i:,. Olympia, Washington April 29,1965 .i::,..

Accelerograph Record

10 seconds Up

0 .o 5g 0 w> .o 5g ------~- 8 >z t:l to 0 t:tj 0 .o 5g t::::i 1 1 tx.1 1Ii I I 1 j 0 • 0 5g ,I I I I I111 ;, I ,1 : l I I l \ I I II I LI : ., I ! 00 d ~ ! I, S86ow < [oi ~~:l\l~IJl~:,'~;1 l;:.!~l~!l~l~Jll~.i~:~ ~\! ·~ i ~ t:tj 1 1 ' " I 111 I 'I I' ~I I ,11~ .RII il!fUI'' W VU'r' "'- -,i , r1 r ~

,0 5g

Figure 29.-Reprotawiea at Olympia, Waahington 0tt, April 29, 1965.

00 w 00 "'"

Tacoma, Washington April 29, 1965

Accelerograph Record 10 Seconds------< ~ tI: t;r.j "'d C:''~~ C: q [.05g I t;r.j East ~ Ul 1 0 E':. ~I w~',·,,·Nt~N , zC: I South ~

00~ :E F'·~~~5g .o zq Carder Displacement Meter Record North ~ 0z t;r.j East >,:I 1-3 tI: [i I:) C: > ~ t;r.j

Figure 30.-Reprolluction. of acce1£rograph and Cartier lli8placement meter records obtained at Tacoma, Washington. on. April !9, 1965. ~ al ,;:,.. en Seattle, Washington 10 seconds April 29, 1965 E:~ :~~~A'/fr;wAV~~

(') 0 > [: 00 ~ > S58°W z t::I ~ [°'' 0 t::I .o 5g ~ j Carder Displacement Meter Record (') 00 d ~ ~ ~ ~ i,<: N32°W ~

Figure Sl.- Reproclucti-On of accelerograpk and Carder cliaplacemen.t meter records obtained at Seattle, Wa8kin.gton, on. A pril !9, 1965.

00 Vl 00 O'I

Olympia, Washington April 13, 1949 Accelerograph Record

1-3

=~ '"d C! ~ 1-3 rn 0 C!z ~ ~ rn= • • -z ~ SW 266° z~ ~ ~ §= ------0 Seconds ------5 10 ------15 20 25 - ~

Figure S!.- Tracing of accelerograph record obtained at Olympia, Waahin.gt011o 011o Ai>ril 13, 1941}. ~ ~ 00

Seattle, Washington April 13, 1949 Accelerograph Record

0 ___ Seconds ___ 5 ______10 ______15 ______20 ______25 ______30 __ _

0 0 >r.n • • i-3 ~ t:, . C) 1:%.l 0 t:, ~i l:tj j 0 r.n ~ <~ 1:%.l ~

0 ___ Seconds ___ 5 ______10 ______15 ______20 ______25 ______30

Figure SS.-Tracinga of acoelerograph records obtained at Seatfle, WaaMngton on April 18, 1949.

00 -..J 00 00

22- Ol YMPIA-ACCELERATION, S4°E COMPONENT

20- ~ II: t_%j 13 APRIL 1949 EARTHQUAKE I I 1 e- "'d 0 d ~ 29 APRIL 1965 EARTHQUAKE q Ou 16- t?=:J w 1--3 ~ - rn Z 14- 0 0 d V) z ~ 12- ~t:, .... u.. 0 10- rn~ ~ w II: co ~ a- -z :::>z ~ G- 0z t?=:J 4- ~ 1--3 II: 2- 0 d 0- I 5 I 6 I 7 I a 1 9 I 10 I II I 12 I 13 1 14 1 15 1 16 I 17 1 18 I 19 I ~ PERCENT GRAVITY

Figure !4,-0omparnOfl. of accelerati

50 COAST AND GEODETIC SURVEY TABLE 8.-Composite of Strong Motion Instrumental Data (Acceleration)

.Acceleration Const.ants Acceleration Station and Component Remarks InstrU• Senst- Maxi- ment T o tlvlty mum Period No. • ------aec. g. 8tC. Beattle cmfo. Vertical •••••...... •••••••• 360 0.08t 19. 6 10 O.Ot2 0.19 0.1 sec waves modulating 0.2 sec 0.038 0. 27 waves. o.ou 0.33 0.019 o. 70 S82°E• .•••••••••••. • . . .•••• 3M 0.083 20.3 10 0. Ol58 0. 27 O.M see waves predominate O.OM O.t& with 0.1 sec of low amplitude 0.061 0.36 oven1dlng. 0.016 o. 7t Sll8°W.... ••••..•••...••.••• 358 0.084 22.3 11 0.082 0.50 Sinusoidal with overriding 0.1- 0.082 0.36 0.2 sec low amplitude waves. 0.07t O. M 0.017 0. 70 Tacoma Vertical •••••••••••••••••••. S.6 o. 078 17. 3 10 0.069 0.07 Irregular short period waves. 0.063 0.22 0.038 0.19 O.CYM 0.83 0.009 0.067 East•.• ••••••• ••••••••••••• S.6 0.078 17.Q 8 0.07t 0.13 Irregular wave form. O. Ot8 0. 71 O.Ot8 0.67 South •••••• - •••••••••••••• 847 0.076 17. 6 10 O. Ot6 0. 21 Un balanced sinusoidal waves. 0.043 0.11 0.017 0.86 Olympia Vertical..-• ••••••.•••••• ••• 807 0.080 18. 8 9 0. 088 O.Ot& Sharp spiked and short period 0.069 0. 11 waves. 0. O'l1 0.113 S4°E•...•. ....••...•.•. .... 276 0. 081 21. 6 8 0. 161 0. 16 Sinusoidal waves. 0.186 0.09 0.084 0. 24 0.012 0.88 886°W••••• ••• •••....••.••• 309 0.080 19. 3 10 0.1118 0.12 Sinusoidal waves. 0.197 0.09 0.009 0.6 Ross Dam Crest Vertical •.•• •••••.••••••••••• 8-3 0.082 20. 0 11 o.ooz 0.8 Weak-0.1 sec waves modulating 0.3 sec waves. S39°E .....••• •..•.•.••..... 8-4 0.087 23.3 10 O.OOt 0.26 Sinusoidal waves. 651°\V •••••..•••••••••••••• 8- 1 0.083 21 .4 10 0.033 0.3 Sinusoidal waves. Portland Vertical • •• .....••••....•••. 229 0.082 20.6 10 0.006 0.16 Sinusoidal waves. N20°E •••...... •...•.... 230 0.084 22. 0 9 0.007 0.21 Irregular. s10°E...... •...... • 231 0.082 20. 7 10 0.007 0.23 Irregular. 90

THE PUGET SOUND, WASHINGTON EARTHQUAKE 51

TABLE 9.-Co,npo.Ste of Strong Motion lnd rumental Data (Du placenunt)

Dlaplacement Meter Coiutani. Diaplacement Station and Component Remarks lllatrU• Btatlc Maxi· ment To M~· mum Period No. tu a • ------,ec. cm. If(, S.tUa N82°W ••.••••••••••••••••.. 12 2.61 0.8 9 0. 76 0.6 0.6 sec waves overrtdlDI U aec 0.78 2. , wavee. O.IIO 4.00 0.'7 uo S68°W.---········ ········ 18 2.46 0.8 10 1.1 8. 70 0.7 eec waves modulatlnJ8.7 eec O.lrl 1. .0 waves. 0.8 0. 78 Tacoma 'ltut ...... 87 8.90 1.0 18 2.0 1.8 A lar,e Ji cycla ,round dl,place· o.sa ,.a ment toward the But at a.o sec 1.8 a.o period. 0.86 1.8 0.42 ,.o North• . ••••••••••••••••...• ae 4.01 1.0 10 o.e1 , .8 0.26 1.06 o.e1 a.a

U.S. GOYDUOIDIT l'!ffllTING onlC[: 11115 0-,,.._ 91

United States Earthquakes 1965

By

Carl A. von Hake

and

William K. Cloud

Jerry L. Coffman, Editor

U.S. DEPARTMENT OF COMMERCE John T . Connor, Secretary

ENVIRONMENTAL SCIENCE SERVICES ADMINISTRATION Robert M. White, A dm{nistrator

Coast and Geodetic Survey James C. Tison, Jr., Dire~tor 92

U.S. GOVERNMENT PRINTING OFFICE WASHINGTON : 1967

For sale by the Superintendent o( Documents, U.S. Go\'ernmcnt Printing Office Washington, D. C. 20402. Price 55 cents.

11 93

32 United States Earthquakes, 1965

Los Angeles.-Felt by many and fright­ December 11: I 0:09:02•. Epicenter 34.7° ened few. Slight damage was reported north, 118.7° west, south-central California, from the Occidental Center Building where W. Magnitude 4.2. Keene. V. Felt by all some minor a·acks in concrete were ob­ in community. Windows, doors, and dishes served on the 30th floor. Small objects rattled; building creaked. Rapid motion in shifted; hanging objects swung moderately southwest-northeast direction; duration, 4 south-north; sharp, jolting shock. Felt by seconds; moderate earth noises from south­ several in the 28-story City Hall where west-northeast. small objects shifted. To observer on the December 20: 10:30:59.0•. Epicenter 5th floor, motion seemed undulating in 40.7° north, 121.4° west, northern Cali­ east-west direction. In a building at 3223 fornia, W. Magnitude 3.7, B. Felt at Min­ West 6th Street, those on 11th floor re­ eral. ported a vigorous north-south sway. On the second floor, a strong jiggling was observed for about 4 seconds. Chandeliers WASHINGTON AND OREGON [ I 20th Meridian or Pacific Standard Time] swayed on the 13th floor of the Merchandise Mart. In the Vernon District, felt by April 29: 07:28:43.6•. Epicenter 47.4° many in a 2-story building. Slight, sharp, north, 122.3° west, northwestern Washing­ jolt. Windows, doors, and bookcases ton, W. Magnitude 6.5. Felt over an area rattled slightly. In the Wilshire District, of approximately 130,000 square miles of lamps figgled and dishes rattled. the United States and British Columbia, INTENSITY 1- 111. Altadena, Culver City. Canada (see figs. 6 and 7) . Three persons Huntington Park, Inglewood, Long Beach, were killed by falling debris-one in down­ Maywood, Pacific Palisades, San Gabriel, town Seattle on South King Street, and two and Walnut. Reported felt (no details) : on Harbor Island at the Fisher Flouring Baldwin Hills, Inglewood, and Santa Mon­ Mills. The deaths of four elderly women ica. from heart failure in Olympia, Port Town­ November 14: 18:02:13.8•. Epicenter send, Seattle, and Tacoma were attributed to 37°44' north, 122° 09' west, central Cali­ the earthquake. There were numerous inju­ fornia, B. Magnitude 2.5. Felt at Berkeley ries, but most were minor. It was reported and Oakland. that more than 30 persons were treated at November 25: 16:58:39•. Epicenter 40.5° hospitals in the Seattle area and dozens suf­ north, 125.0° west, off coast of northern fered minor injuries elsewhere. Damage California, W. Magnitude 4.0, B. Eureka. was estimated at approximately $12.5 mil­ Reported as "not felt by all." lion by the State Civil Defense Department, December 2: 23:34:58.4•. Epicenter 35.3° with most of it occurring in King County. north, 118.5° west, south-central California, Although a maximum intensity of VIII \IV. Magnitude 3~, P. Keene. IV. Felt by was assigned to some pocket areas of West many_ in community. Building creaked and South Seattle and at Issaquah, this slightly. Slow motion of 3 seconds' dura­ earthquake is best described as one with a tion; preceded 2 seconds by moderate eartl1 maximum intensity of VII. Some of the noises. more spectacular damage was difficult to December 3: 03:00. Keene. IV. Felt by evaluate since many buildings in Seattle many in community. Slow motion; lasted and other Puget Sound areas had been l second; preceded by faint earth noises. damaged ·by previous earthquakes, notably December 3: 14:49:50.9•. Epicenter 34.2° the April 13, 1949, shock. The following north, 117.1 ° west, southern California, \V. paragraphs are excerpts from pages 27-39 Magnitude 3.5, P. Felt at San Bernardino. of the Preliminary Report, issued by the 94

Summary of Em·thquake Reports 33

118°

B R T S H C O L U M B • •

so• limits of Fell Area ) • ./ • 0 e Penticton 0 Oo ) Vancouver o 0 • 0 ' .. ------;,:~--fg~-;-,tl . 0 I-IV o ~. e.okohe 0 .P l O 0 o' 8<} o o

F1CURE 6.-Area affected by Puget Sound, IVasfi., ea rthquake of April 29. 95

34 United States Earthquakes, 1965 123° 122°

0

0 V 0

0

STRAIT OF Q 5 VI JUAN DE FUCA 0

.480 48° Q 6 0 6

0 Od 0

123° 122°

FIGURE 7.-E.picentral area of Puget Sound, Wash., earthquake of April 29. 96

Surnr11ary of £arthquake Repm·ts 35

Coast and Geodetic Survey, covering this tools and \\OOd -~upponcd floors, and is not earth· earthquake.4 qual..c· resisti,e i11 any sens('. :\'u111cro11s instances of paraper and gable laih11 c occurred. and death .Building dama!!,C was ge11crall ) ligln. although it and injury rc.,ultt:tl !rom this t))'(' ol damage. As was spectacular in many c:ise~. ·1 oral collapses die! prcdoLtsly me111iom:d, som(' ol this 1.011 1d he associ· not occur as far as is k nown "' the au1h01s. In ;ired with the 1919 earthquake clantai;c ;is well as gc11eral, damage patterns re1wa1cd tho,c of the with scllktnent damage which was tHll related to 1949 shock. Buildings which appan:ntly fwd bee11 e..rthqu::tkc~ ... damaged in 1949 often suswined additional damage in 1965. This reoccurring carth(ptakt· damage was A classic case cif cumulaLi,e damage: was found 011 the mud fl.its of rac-oma. A LM>-Stoq hrick hear· sometimes intermixed wi r h pn•carthcpiakc settle­ mg wall Lmilding wa~ sii;11if1cantly ·damaged in the ment cracks which opened wider 01 caused faih11c 194!1 shod.. and the second SLOI) was subsequently i11 the 1965 eanh~uakt'. 1cmo,·cd. Ir was :1pparem when inspected alter the Single family dwellin!!,'S in 1hr. afftct<:ragc hctwee11 change radically within several city block~. As a the roof diaphragm and its cud shcat wa ll. The rule. wood-franw dwelling damage rarelv ap­ rnol mO\l<'d hack and forth owr the end slwar wall, proached as mud1 as 5 percent of building value. dantaging the sidl· walls. ~, Sl'COnd instance of One exception to the foregoing rule was unit damage to a building prcsun1ablr imcnded w be mason ry veneered wood-frame structures, particu­ carrhquakc rcsisti,·e ocnarrcd at a one·stor)' market larly brick veneer. Four-inch l>rick veneer peeled in which the steel angle e:1rthquakc X·hracing wa, off a number of wood-frame suuctures even though e mberlckd in a hollow rnncrett> b lock wall; the the veneer was anchored LO the wood-l>acking wall relative rigitlilics ot the clements were such that with galvanized metal anchors. The anchors usuallv the hollow co11c1 e tc hlock had to fail before the remained nailed lO the wood frame when the brick steel X-bracing could function Aclditionall)', the peeled off, and an examination of the mortar in di­ X-bracing was ~o located as to cut in two most of cated Lhat the mortar could be crushed b y hand. lht: wall reinforcement. A third instance of note This type o( veneer damage has been noted in was a large man11 facturi11g f.tcilitr having ;; verr many previous earthquakes .... 1:irge floor area; the sccoml-st0ry precast reinforced Multistory buildings generally had slight or no concrete panels appeared to ha\'e worked loose damage, with the damage reponed 10 new and Lo fiom their supporting frame. The fourt11 example o ld structures. Plaster cracking and other non· was a four-story hollow concrete•hlock aparrmcnt structural damage was found in multistory build· house in whid1 the block shattered ar Sl'veral loca· ings in Seattle as well as in Tacoma (these cities Lions, ancl a remarkable absence of \'Crtical reinforc· bei.ng about 30 miles apart). The spectacular ing slecl was noted .. .. ~amage reported by the press to a IO·slory building U ti lily damage was nol severe. Excerpls m Tacoma may have been entirely confined Lo ex­ (pages 41-42 of the Preliminary Report) terior window glass in a structure having essentiallr a 11 glass on three sides. with the fourth side solid. of the summary prepared by the ·washing­ Unreinforced brick·bearing wall buildings with lon Surveying and Rating Bureau fo llow: sand·lime mortar. as usual, bore the brunt of the Service from the various public utilities was, on damage. This type of building generally bas wood the whole. uninterrupted. Damage at the Spokane Street Substation interrupted service in a small 4 The Puget Sound, Washington Earthquake of April 29, 1965, U.S. Department of Commerce, Coast and Geodetic area. The Washington Natural Gas Company Survey, 51 pages, 1965. reported one minor break in t11e Purallup area. 97

36 United States Earthquakes, 1965

The Seaule \Vater Department had one break in a cc,nsisted or plaster cracks, missing chimney bricks, 12-inch main in the Harbor Island area and minor and things of this nature. The remaining 951 breaks in small pipes in residential area~ of unstal>le buildings were either found to have suffered no ground. Four days after the eanhquake. a break apparent damage, or damage was so slight that it in a 20-inch main on Western Avenue at Spring co uld not be readily recognized. Street resulted in water supply impairment fur about one day to four sprinklered buildings sup­ Strong-motion earthquake records "·ere plied off this main. obtained from Coast and Geodetic Survey In Everett. two of the three 48-inch main supply stations located at Olympia, Ross Dam, conduits lo the city failed. These failures occurred Seattle, and Tacoma, Wash., and from where the lines arc carried on trestles over .Ebe) Portland, Oreg. Slough . . . Full service was restored the following day. One other break was reported in a 4-inch Temporary seismograph stations were in­ I inc in a residential district. stalled by the Coast and Geodetic Survey A number of breaks occurred in underground at Bremerton, Issaquah, Seattle, Pacific, mains on plant sites and to overhead sprinkler and Enumclaw to record aftershocks. Dur­ piping. These were mainly to those properties located on artificia l fills in the ,outhcrn part of ing the 14 days of operation of the tempo­ SeatLle, particularly Harbor Island, resulting in rary seismograph stations, only one after­ \'arying periods of impairment . . . Damage to shock was recorded at a sufficient number over,head spnnklcr piping was mainly to older of stations to permit an epicentra.J location. systems without earthtptake bracing and Acxible Twenty-seven aftershocks were reported couplings. An exception was to a number of newer systems in buildings loc:ued on artificial fil l but could not be located because of insuffi­ where suspended ce ilings and light fixtures damaged cient data. No aftershocks were reported sprinkler heads and piping. felt. The following are excerpts from a letter INTENSITY VUI: report written by Fire Chief Cordon Vickey Issaquah (about 15 miles southeast of (pages 42-43 of the Preliminary Report) : Seattle) .-Felt by and frightened all in In the clay or two following the earthquake, il community. Brick garage partially col­ l.,ecame evident lhat the Fire Deparuncnt, working lapsed. Both of the old, 2- and :3-s tory, in conjunction with the Building Department. brick junior high schools were extensively might be in a position to render valuable scn·icc damaged. There were Jong jagged cracks hy conducting a building-by-building surVC), to more ac:curatcly assess the extem or damage from in exterior and interior walls. Daylight the quake. The effort was coordinated between could be seen through some of the cracks. the Fire Department, Building Department. and At ground level, there were long, broken rcprcscntati,·es of the U.S. Army Corps of Engi­ separations in concrete walkways. Light fix­ neers. On May 3. four days after the earthqua kc tures were tilted and askew. Chimney dam­ struck, our personnel were out in force act11ally conducting this survey. age was very prevalent in the area and ex­ tensive damage was reported tO liquor stock One survey w<1s conducted on a continuous basis from May 3 through Ma y 21. During this time, a in stores. Rapid motion in north-south di­ total of l,440 man hours were expended, and 1,405 rection; loud earth noises. buildings were surveyed from roof to basement. Seattle.-Felt by all an'd frightened many As a result of the snn,cy, 91 buildings were found in community. Extensive damage to chim­ to have sustained apparent serious or extensive damage, and were recommended to the Building neys was noted in West Seattle. In 188 city Department for resur\'ey by experts as rapidly as blocks, it was found that 1,712 chimneys of possible. One hundred and thirteen buildings were the 5,005 were damaged. Two schools in found to have s11stai11cd apparent moderate damage, West Seattle were also ext~nsively dam­ and were recommended for resurvey as Lime and aged. Slumping- was observed along a steep person11el would permit. Two hundred and fifty buildings were found to have sustained superficial slope adjacent to 36th Avenue S.W., near or light damage only. In this group there was no Admiral Way. Eight Seattle public schools apparent need for a follow-up survey, as damage were closed until their safety cou'ld be 98

S1, mmary of Earthquake Reports 37

established. Of Lhese schools, the West Alki dock wwar

38 United States Ea,·thquakes, 1965 the force of the shock, crinkling blacktop fell from the front of the 16-story building, around the Agua Theater and opening Lig­ but were prevented by ledges from reach­ :tag fissures in the ground. A concrete wall ing the sidewalk. At the Frederick & Nelson buckled at the junior crew house at the Store, minor damage was reported to the Aqua Theater, wrecking it possibly beyond store and stock. Some walls were cracked repair. Other Park buildings suffered minor and mannequins toppled. A spokesman re­ cracks and small patches of dislodged plas­ ported: "Our building and the adjoining ter. Water spurted 15 feet in the Lower Medical Dental Building teetered apart a Woodland baseball field due to a water bit, then came back together with a loud main break. Another smaller main split at clap." Evans Pool at Green Lake, but the pool Trans-World Airlines Building (opposite remained open. Maplewood Place S.W .. the Olympic Hotel) .- Severe damage on near Three Tree Point, settled. The fol­ ground floor. The middle of one ground lowing building damage: was rcponed hy wall was severely cracked. A front panel the press: window, about 8 by 12 feet, slipped away Art's Food Center (9999 Holman Road from its casement. N.W.) .-Gaping holes in four concrete Union Pacific Railroad Station.-A sec­ walls. Merchandise fell from shelves. tion of heavy cornice atop the west side of Ballard City Hall (Ballard Avenue N.W. the station fe:I and crashed through the and 22nd .-\venue N.W.) .- Sidewalks adja­ sidewalk. ·fhe third floor sagged, and walls cent to the old Ballard City Hall were bar­ and ceilings were cracked. The station was ricaded due to bricks falling from the old evacuated. structure. Press repJ,·ted the following school dam­ Boeing Aircraft Company facilities.­ age: Many windows broke in the south side of Ballard High School.-Damage was con­ the Boeing Administration Building and fined to the auditorium, where a ceiling the adjoining Engineering Building. Minor arch was bent and a study wall twisted. damage was reported in Plant No. 2, mostly Broadview Elementary School.-Part of broken windows and cracked walls. Some the east, brick-exterior wall fell at the old damage was reported at other Boeing facil­ section of Broadview's plant. ities, including the Development Center, Colman Elementary School.-Chimney south of Plant No. 2. There were no re­ damage; part of the masonry gables at the ports of injuries other than scratches and entrance fell; front wall damaged. bruises. Franklin High School.-Parts of cornices Federal Office Building.-Extensive dam­ on four corners of the building fell; lunch­ age was reported to the upper floors of the room ceiling cracked; hallway and stair­ I 0-story building. Employees above the well were damaged. All fire alarms were third floor were sent home. short-circuited and activated. First. Avenue S.- Sidewalks south of Yes­ Gatewood Elementary School.-Gables ler Way were littered with bricks cracked fell. loose from the tops of older buildings. At Leschi Elementary School.-Gables fell. 2716 • 60th Avenue S.W., an entire chim­ Madison Junior High School.-Chimney ney and front wall fell, leaving the living collapsed and masonry fell at the entrance. area exposed. Several cracks occurred in upstairs rooms at Medical Dental Building (509 Olive the Administrative and Service Center. Way) .-An 8-pound piece of cornice fell Waterline was broken also. on the sidewalk on the Fifth Avenue side Queen Anne High School. - Walls of the building. Small chunks of masonry cracked. 100

Summary of Earthquake Reports 39

St. Joseph's School.-Pieces of cornices able plaster damage, particularly in the fell from front o( building. middle floors. University of Washington.-New cracks Providence Hospital.-Many interior wall appeared in partitions of the Mechanical cracks. The sixth-floor surgery department Engineering Building, under repair since was closed for two hours due to plaster early in the year. Three large planks were dust in the operating rooms. Two doctors bolted to the cement-block wall of a second­ were trapped when an elevator jammed floor classroom after inspection. Damage to after dropping from the sixth to the third the structure was reported as minor. ln floor. the crew house, the section where the new St. James Cathedral.-Low-hanging sleeping quarters adjoined the older sec­ chandeliers swayed violently. Priest left tion was cracked about an inch. Minor the sanctuary when he was showered by cracks on the fourth floor of the new li­ falling debris. Minor damage. brary were observed. Electric cable broke Seattle Times Building.-This 2-story in the Mechanical Engineering Buildings. concrete building shook "like an electric It was reported that the tops of 60-foot trees vibrator." Plaster sifted down in rooms swayed 3-4 feet, and that a fissure opened and teletype printers stopped work briefly. in the practice field at the University. Smith Tower.-Woman in penthouse on Underground pressure from the shock sent top the tower reported she was rocked out sand spurting in a 100-foot-long zig-zag of bed. Extensive cracks and plaster stretch on the lower football field. Behind damage were reported on the 33rd floor. the men's pool, areas of the ground Substation at 4th Avenue S. and South dropped as much as a foot. Dirt floor sec­ Spokane Street.-City Light Company re­ tions in the Hee Edmondson Pavilion also ported damage at its substation cut off sank slightly. At the Wesley Foundation, a service to some industrial plants, including car was badly damaged by falling bricks the Seattle Foundry. from a chimney. Todds Shipyards Corporation (1801 - West Seattle High School.-Severe crack­ 16th Avenue S.W.) .-Bricks from fallen ing of walls throughout the school. Both chimney damaged parked automobiles and exterior and interior walls of the auditor­ broke a second-floor window. ium were cracked. INTENSITY VII: Whittier Elementary School.-Pupils Allyn.-Felt by and frightened all in were evacuated from second floor due to community. Damage to brick, masonry, structural damage. and concrete. Chimneys twisted and fell. Additional press reports of minor dam­ Plaster, chimneys, and ground cracked. age are as follows: Dishes broke. Furnishings shifted; small Bayview Manor Retirement Home.- objects overturned. Person outdoors saw Doors jammed. Elevator inoperative. the house sway north-south "about 2 feet Large crack in ceramic mural. each way." Rapid motion in northeast Blessed Sacrament Church (9th Avenue direction; loud noises from north heard. N.E. and 50th Street N.E.) .-Possibly seri­ Auburn.-Felt by all; awakened and ous damage to the tower. frightened many in community. Damage Bon Marche Store.-Major damage oc­ slight. Few chimneys twisted and fell. Few curred to china. "You can see where the dishes and windows broke. Plaster, win­ sky bridge (connecting the Bon Marche dows, and chimneys cracked. Knickknacks and the Third and Stewart parking garage) fell. Small objects shifted and overturned. moved about 2 inches out of line." Press reported Auburn schools were closed King County Court House.-Consider- until buildings were checked. The city 101

40 United States Earillqual

Summary of Earthq uahe Reports 41

pictures, and plaster fell. Plaster, windows, and windows broke; pictures and plaster walls, chimneys, and ground cracked. fell. Furniture shifted; small objects over­ Small objects and furnishings shifted; vases turned. Rapid motion in east-west direc­ and small objects ovenurned. Trees and tion; duration, 1 minute; preceded by bushes shaken strongly. Motion rapid; moderate earth noises. loud earth noises. Everett.- Felt by and frightened all in Duvall.- Felt by all and frightened many community. According to press reports a in community. Damage slight to wood, State Patrol radio tower toppled and brick, masonry, and concrete. One chim­ streets buckled. A water main broke ney fell. Plaster and chimneys cracked. between Everett and East Everett. Chim­ Knickknacks, books, and pictures fell; ney damage and downed power lines were small objects shifted; vases and small reported from various areas. The Bonne­ objects overturned. Hanging objects swung vi Ile Power Administration reported three east-west. Rapid motion in east-west direc­ major lines went out of operation. Two tion; duration, 1 minute. 230,000-volt lines from Chief Joseph Dam Eatonville.- Felt by and frightened all. to the Snohomish substation near Everett Damage slight. Plaster and walls fell. were toppled. Another 300,000-volt line Dishes, windows, and furniture broke. from Grand Coulee Dam to Olympia was Plaster; windows, walls, chimneys, and broken. Other observers reported: Plaster ground cracked. Knickknacks, books, and and chimneys cracked. Knickknacks and pictures fell; small objects and furnishings books fell; small objects shifted and over­ shifted; vases, small objects, and furniture turned. Motion rapid; duration, 45 overturned. Pendulum clock stopped. seconds; preceded 5 seconds by moderate Slow motion in north direction. earth noises. Elbe and vicinity.-Felt by all and fright­ The following is an excerpt from a re­ ened many in community. Damage slight port by the Washington Surveying and to brick. Chimneys cracked, twisted, and Rating Bureau: fell. Knickknacks and pictures fell. Fur­ In Everett, lwo of I.be lhree 48·inch main supply nishings shifted. Trees and bushes were conduits to the city failed. These failures occurred shaken strongly. "Some people seemed to where the lines are carried on trestles over Ebey think that the motion was in several direc­ Slough. Industrial supply to the large consuming pulp mills was then shut down, the mills either tions. Parked cars jumped up and down. closing down or going to river pumps. Full service Dishes did not fall from east-west facing was restored the following day. One other break cupboards. Two people reported feeling a was reported in a 4-inch line in a residential light tremor on April 30, about 9: 10 a.m." district. Motion rapid; duration, I minute; mode­ Gate.-Felt by J!lany and awakened few. rate rumbling. Damage slight. Chimneys cracked, twisted, Electron (near Orting) .-Felt by and and fell. Small objects shifted and over­ frightened all in community. Damage to turned. Slow motion north-south; pre­ masonry. Chimneys, columns, and monu­ ceded several seconds by loud earth noises. ments twisted and fell. Dishes, windows, Gig Harbor (Kitsap Peninsula) .-Press and furniture broke; walls fell. Ground reported a part of Crescent Lake Road, cracked. Trees and bushes shaken strongly. west of Gig Harbor, sank out of sight and Rapid motion in northeast direction; dura­ was covered with water. tion, 10 seconds. Gold Bar.- Felt by all and frightened Enumclaw.- Felt by all and frightened many in community. Damage moderate. many in community. Damage considerable Chimneys twisted and fell. Dishes, win­ to brick. Chimneys twisted and fell; dishes dows, and furniture broke. Knickknacks, 103

42 United States Earthquakes, 1965

books, pictures, plaster, and walls fell. Trees and bushes shaken strongly. Dura­ Plaster, windows, walls, chimneys, and tion, 45 seconds; east-west direction; earth ground cracked. Small objects and furnish­ noises from east-west. ings shifted; vases, small objects, and fur­ Kapowsin.- Felt by all and frightened niture overturned. Trees and bushes many in community. Damage slight. Chim­ shaken strongly. Motion rapid; duration, neys twisted and fell. Windows broke. 45 seconds to 1 minute; loud earth noises. Plaster, windows, and chimneys cracked. Gorst.-Felt by all and frightened many Knickknacks, books, and pictures fell. in community. Damage considerable. Small objects shifted; vases and small Chimneys twisted. Dishes broke. Small objects overturned. Trees and bushes objects and furnishings shifted; vases and shaken strongly. Motion rapid; duration, small objects overturned; knickknacks, about l minute; loud earth noises from books, and pictures fell. Motion rapid; north. duration, 40 seconds; preceded 40 seconds Kenmore.- Felt by all in community; by moderate earth noises. frightened few. Damage considerable to Granite Falls.-Felt by all and frightened masonry. Some chimneys, columns, and many in community. Damage slight. monuments fell. Dishes, windows, and Chimneys twisted and fell. Dishes broke. furniture broke. Knickknacks, books, pic­ Small objects shifted; knickknacks, books, tures, plaster, and walls fell. Some plaster, pictures, and plaster fe ll. Trees and bushes windows, walls, chimneys, and ground shaken strongly. Hanging objects swung cracked. Small objects and furnishings east-west. Duration, 45 seconds; east-west shifted; vases, small objects, and furniture direction; moderate earth noises. overturned. Trees and bushes shaken Grapeview.-Felt by and frightened all strongly. Hanging objects swung east-west. in community. Damage to brick, masonry, Rapid motion in east-west direction; dura­ and concrete. Dishes broke. Plaster, chim­ tion, 45 seconds; moderate earth noises. neys, and ground cracked. Knickknacks, Kent.- Felt by all and frightened few in books, and pictures fell. Small objects community. Press reported general build­ and furn ishings shifted; vases, small objects ing and window damage. Bricks fell off and furniture overturned. Trees and the old Armory onto parked cars, but no bushes shaken strongly. Rapid motion in one was injured. One water main broke north-south direction; duration, 40 seconds. and several wires snapped. Plaster and Grotto.- Felt by and frightened all in walls cracked. Furnishings shifted; vases, community. Damage slight to brick and small objects, and furniture overturned. masonry. Chimneys twisted and fell. Hanging objects swung east-west. Motion Plaster and chimneys cracked. Small slow; preceded 10 seconds by loud earth objects and furnishings shifted, including noises from east-west. piano; small objects overturned. Pendu­ Kingston.- Felt by and frightened all in lum clock, £acing south, stopped. Motion community. Damage considerable. Chim­ rapid; duration, 1 minute; faint earth neys twisted and fell. Dishes and windows noises. broke. Plaster, windows, walls, chimneys, Hobart.- Felt by all in community. and ground cracked. Knickknacks and Chimneys fell. Dishes, windows, and fur­ pictures fell. Small objects and furnish­ niture broke. Knickknacks, books, pic­ ings shifted; vases, small objects, and fur­ tures, plaster, and wall fell. Plaster, win­ niture overturned. Trees and bushes dows, walls, chimneys, and ground cracked. shaken strongly. Rapid motion in north Small objects and furnishings shifted; vases, direction; duration, 1 minute; loud earth small objects, and furniture overturned. noises from north. Press reported the road- 104

S111nm11ry of t:.arthqualle Reports

way 2 miles west uf Kingston on Highway and plaster £el I. Small ohjects shifted; 104, near the vVolfe 3chool, was damaged, vases and sma II 0bject$-overturned. Trees but not dosed. and bushes shaken strongly. Slow motion Kirkland.- Felt by all and frightened in steady, rolling, north-northwest direc­ many in r.ommu111ty. Damage slight to tion; dmation, :ibout I minute; preceks. pictures, and and furniture overturned. Motion rapid; plaster fell. Plaster, walls, chimneys, and moderare earth noises. gro~nd cracked. Earth aacks along canyon Longbranch.-Felt hy all and £rightened of the Nisqually River; slides into rivers many in r.01111nunity. Damage considerable. and onto roads. Small objects dnd furnish­ Chimneys twisted and fell. Dishes broke. irlgs shifted; small objects overturned. Cars Knickknacks. books, piccures, and plaster outdoors rocked north-south. Trees :md fell. Plaster and chimneys cracked. 3mall bushes shaken strongly. Pendulum clock objects shifted; vases and small objecL~ facing east stopped. Rapid, sharp motion overturned. Trees and bushes were shaken in north-south direction; duration, nearly strongly. Rapid motion in east direction; I minute; loud earth noises at beginning duration. '.30 seconds; preceded about 12 of shock. seconds by moderate earth noises from Lakebay.-Felt by all and frightened east. "After shock had quieted down. many in community. Damage slight to light fixtures and other hanging objects brick. Chimneys twisted and fell. Small were swinging east-west." objects overturned; knickknacks fell. Mo­ McCleary.- Felt by and frightened all. tion slow; duration, 2 minutes; direction Damage slight co masonry and concrete. north-south; sharp vibration at first; ending Chimneys twisted and fell. Dishes and with gentle sway; moderate earth noises. windows broke. Knickknacks, books, pic­ Lake Stevens.-Felt by all and frightened tures, and walls fe ll. Plaster, windows, many in community. Damage slight. waJls, and chimneY.s cracked. Small objects Chimneys twisted and fell. Plaster and and furnishings shifted; vases, small objects, walls cracked. Trees and bushes shaken and furniture overturned. Merchandise strongly. Pendulum clock stopped. Hang­ fell from store shelves. Light fixtures hang­ ing objects swung east-west. Slow motion ing from ceiling in post office were in east-west direction; duration, 50 seconds; loosened. "To me, the shake seemed more preceded 7 seconds by loud earth noises severe than that of 1949. This time l was from east. in a masonry building; in 1949' I was in a Lakeview.-Felt by all and frightened wooden building." many in community. Damage considerable Manchester.-Felt by all and frightened to brick and masonry. Plaster, windows, many in community. Damage considerable walls, and chimneys cracked. Dishes and to brick, masonry, and concrete. Chimneys windows broke. Knickknacks, pictures, twisted and fell. Plaster, walls, chimneys, 105

44 United States Earll1q11alies, 1965 and ground cracked. Knickknacks, books, neys cracked; one fell. Small objects and pictures fell. Dishes broke. Small shifted and overturned in few instances. objects shifted; furnishings shifted 3 inches; Slow motion in northeast direction; dura­ vases and small objects overturned. Rapid, tion, 1 minute; moderate earth noises from intense motion in east-west direction; mode­ northeast. rate earth noises from north-northwest or North Bend.- Felt by all and frightened east. many in community. Damage considerable Maple Valley.-Felt by all and frightened to brick, masonry, and concrete. "This many in community. Damage slight. Chim­ shock caused more damage in this area than neys twisted and fell. Plaster, windows, any shock during the past 50 years." Chim­ and chimneys cracked. Knickknacks, books, neys twisted and fell. Plaster, windows, and plaster fell. Dishes and windows walls, and chimneys cracked. Knickknacks, broke. Small objects and furnishings books, pictures, plaster, and walls fell. shifted; vases and small objects overturned. Dishes, windows, and furniture broke. Trees and bushes shaken strongly. Slow Small objects and furniture overturned. motion in west (?) direction; moderate Trees and bushes shaken strongly. Rapid earth noises from west (?) . Press account motion in east direction; duration, l min­ stated the County Engineer reported fairly ute; preceded IO seconds by loud earth extensive damage to the county's South noises from east. Press reported an ex­ Road District shops. The water system, tensive slide occurred on the southwest electrical shop, and service station were slope of Mount Si n·ear North Bend; heavy hard hit. Damage to the shops was esti­ damage to liquor stock at North Bend. mated at $10,000 or more. Slides were Oakville.-Felt by all and frightened few reported on the Jones Road and Devils in community. Damage slight to concrete. Elbow Road near Maple Valley. Chimneys twisted and fell. All chimneys Milton.-Felt by all and frightened many were down on a hill in the northwest corner in community. Damage slight. Chimneys, of town. New fireplace moved 1 inch columns, and monuments fell. Knick­ and chimney broke and twisted. Dishes knacks, books, pictures, plaster. and walls and windows broke. Plaster, windows, fell. Dishes, windows, and furniture broke. walls, and chimneys cracked. Knickknacks, Plaster, windows, walls, and chimneys books, and plaster fell. Small objects over­ cracked. Small objects and furnishings turned. Two shocks about I minute apart; shifted and overturned. Trees and bushes preceded by moderate earth noises. Power shaken strongly. Hanging objects swung poles swayed north-south during first shock north. Rapid motion in north direction; and east-west during second shock. Several duration, 45 seconds; moderate earth noises persons at first thought it was a sonic boom. from north. Olalla.-Felt by and frightened all in Mineral.-Felt by all and frightened community. Chimneys twisted and fell. many in community. Damage slight. Chimneys and ground cracked. "Our home Chimneys twisted and fell. Dishes broke. on hill next to post office had main chim­ Chimneys cracked. Knickknacks, books, ney knocked down and house pulled away and pictures fell. Small objects shifted about 3 inches from fireplace chimney and overturned. Trees, bushes shaken (half-way . up) . House sunk in several strongly. Slow motion in north-south places. There are quite a number of chim­ direction; duration, 50 seconds; moderate neys gone in this area." Merchandise fell earth noises from north-south. from shelves in grocery shore; knickknacks, Montesano.-Felt by and frightened all books, and pictures fell. Small objects and in community. Damage slight. Few chim- furnishings shifted; vases and small objects 106

S11111111ai y of earthquake Reports 45

overturned. Rapid, jerky motion; loud means tha1 chirnne) bricks were dislodged or chim­ earth noises. ne)S were destro}ed and interio1 plaster cracked .111d rctl. Abou1 15 percent or the Eastside and Olympia.-Felt by and frightened all in Wc,tside reported moderaie IO heavy chimney community. The following is from press damage and there were a lew teJ>0rts of plaste1 repons: The Union Pacific Railway re­ d:nnage. Fi"e pc1cc11t of the Carl}on-Esi;ridge area ported a hillside fill slid away from beneath 1cpor ted 111odcra1c to he.a ,·) chimney damage, and a 400-foot section of a branch line just rough!~ to percenl 1epo11cd pla~1er d:im:ige. The CapiLO I a1ea seemed to h:He fared considerably outside of Olympia. In the Temple of ,,·orse than 1he 01hcr three areas, al least as far as Justice, cracks developed in the walls of the chimne} ti.image was concerned. .\bout half the law library; cabinet tipped over; books responses from 1his area reported moderate 10 scattered around the floors; pictures fell SC\'c:rc chimney damage. l'irtecn percent reported from walls. In the Legislative Building, moderate plaster damage. Both north-south and ca,L·\\'CSt ditections of motion were reported. there was a crack about 3 feet long on the inside of the inner dome of the rotunda. Other observers in Olympia reported the The 5-ton chandelier swung on its I JO-foot 'ollowing: Most objects in the General chain, like a pendulum clock, in a 1-foot Administration Building, 3rd floor, fell orbit for half an hour after the shock. There from shelves racing north-south; east-west were reports the dome had shifted. The facing shelves lost few objects. Files and building superincendem reported some bookcases shifted up to 3.5 inches. Motion stones weighing 25 pounds or more had seemed to start abruptly. No aftershocks broken loose. Cracks, due to the 1949 were felt. No agitation could be seen on shock, were reopened in the Executive the surface of Capitol Lake about 100- 150 Mansion. Glass from chandeliers in the yards away. At the post office, light fixtures ballroom cascaded to the floor. Light fell. Small objects and furnishings shifted; fixtures were torn out of the ceiling on the small objects overturned. Rapid, explosive­ top floor of the Health Building. The like motion in east-west direction; loud water-pollution laboratory was a tangled earth noises. Four miles south of Olympia mess of broken bottles and other equip­ (Municipal Airport), Celt by many; general ment. The new post office was damaged alarm. Damage was slight to buildings. considerably and ordered closed. A road Some chimneys cracked and pulled away around Capitol Lake, at the base of the from houses; a few north-south and vertical Capitol complex, was damaged, allowing cracks in airport building. Slight displace­ water to flow beneath the road. St. Peter's ment of hanging electrical fixtures. One Hospital reported four persons were treated jarred loose from ceiling. Many objects for minor injuries. Damage to light fix­ were displaced or knocked to the floor tures and elevator shafts in the Capitol throughout the area. Plaster cracked in a Building was about S200,000; damage to few localities, and pieces were thrown down the road and railroad was estimated at the in some inHances. "No landslides in this same amount. area, but there were some in the surround­ The following is from a report by the irtg area." Motion bumping, swaying, Washington State Division of Mines and rapid onset; loud, rumbling earth noises. Geology: Orting.-Felt by all; awakened and fright­ The questionnaires (newspaper canvass) verified ened many in community. Damage con­ our personal observations that the greatest dam:ige siderable to brick. Chimneys twisted and occurred in the area hetwee11 15th A'"enue and 20th fell; windows and furniture broke. Plaster, Avenue and between Capitol Way and Cherrr Street. Damage was rated as none or light (interior windows, walls, and chimneys cracked. plaster cracks and mortar cracks in chimne)s) Small objects and furnishings shifted; vases, versus moderate to heavy. This latter classification small objects, and furniture overturne-' 107

46 United Stat,:s E11rtl1q11akes. 1965

Rapid morion in north-5011th directirm; Poulsbo - Felt by and frightened all in duration. 35 seronds; preceded 2- 3 se<:onds community. Damage slight. Chimneys by loud earth noises from north-south. 1 wisted and fel I. Plaster, walls, and c.him­ Pacific- Felr hy ,md frightened all in neys cracked. Dishes broke. Knickknacks community. Chimneys twisted anJ fell; and pictures fell. Small objects and fur­ chimnevs cracked. Knickknacks and pic­ nishings shifted; vases and small objects tllres fell. Fmnishings shifted; furniture overtmned. Trees, bushes shaken strongly. overturned. Trees, bu~hes shaken :strongiy. Pendulum doc-k, facing west, stopped. 5Iow motion in north-south direction; Rapid motion in so11therly direction; ~lura­ duration, 2Vi minutes; preceded by loud tion, 45 seconds: moderate earth noises earth noises from nMth-south. from southerly direction. Palmer.- Felt by all :md frightened Preston.-Felt by all : awakened and many in community. Damage slight. frightened 1nany in community. Damage Chimneys twisted 1.nd fell; chimneys slight to brick. Chimneys fell; chimneys cracked. Knickknacks. books. and pictures cracked. Dishes broke. Knickknacks :md fell. Small objects ;ind furnishings shifted: hooks fell. Small objects shifted and over­ vases, small objects overturned. Trees. turned. Trees. bushes shaken strongly. bushes shaken strongly. Motion rapid: Motion 1<1picl; duration, 45 seconds. ·'Shock duration, 30 seconds; loud eanh noises. began with several ~econds of vibration in Peshastin.-Fi!lt by all and awakened north-south direction, rapidly increasing few. Danugc considerable. Chimneys in speed and intensa y: then followed he:wy twisted :md Cell. Plaster .incl chimneys shocks o l undulating and rocking motion, cracked. Knickknacks and pictures fell. accompanied hy earth noises. R ocking Small objects shifted and overturned. continued for several seconds after rumbl­ Motion rapid; duration, I minute: mode­ ings ceased." rate earth noises from northwest. Puyallup (a bout :30 miles south of Seattle) .-Felt by and frightened many in Portage.-Felt by all and frightened many conrntunity; awakened few. Damage <:011- in community. Damage slight. Chimneys siderable. Chimneys and walls fell. Plas­ fell; chimneys cracked. Dishes broke. ter and chimneys ,racked. Dishes and win­ Small objects shifted; vases and small dows broke. Knickknacks, books, and objects overturned. Rapid motion in east­ plaster fell. Small objects and furniture west direction; duration, I minute; loud earth noises. overturned. Trees, bushes shaken strongly. Pendulum clock, facing south, stopped. Port Orchanl.-Felt by all and frightened Rapid, rolling motion in north-south direc­ many in community. Damage considerable tion; loud eanh noises from north. The in masonry and concrete. Brick chimneys Washington Natural Gas Company re­ fell. Walls, floors, chimneys, and ground ported one minor break in tlie Puyallup cracked. Windows broke. Telephone area. service disrupted. "Many homes and busi­ Quilcene.- Frightened all in community; nesses reported fallen pictures from walls awakened many. Damage considerable. and broken dishes from cabinets and shelv­ Plaster and w,1 lls fell; plaster, windows, ing." Pendulum clock, facing east, stopped. walls, chimneys cracked. Dishes, windows, Rapid motion in southwest direction; dura­ and furniture l,roke. Knickknacks, books, tion, 45 seconds; preceded about 6 sec:onds and pictures fell. Small objects and fur­ by moderate earth noises from southwest. nishings shifted; vases, small objects, and Press reponed the highway a mile east of furniture overturned. Trees, bushes Port Orchard was cracked. shaken strongly. Pendulum clock stopped. 108

S11111111a1y of c.artl,qunl

Rocking motion in north-south direction; in community. Damage slight. Chimneys loud earth noises. cracked and fell. Pictures fell; small Ravensdale.-Felt by all (except people objects and furnishings shifted; vases, small in cars) and I rightened many in com­ objecls, and furniture overturned. First munity. Damage sl ight. Chimneys twisted shock fairly light; second, rapicl strong and (ell; plaster fe ll ; plaster and chimneys shaking in east direction; duration, 45 cracked. Knickknacks, books, and pictures seconds; accompanied by earth noises. fell. Small object!, shifted; vases and small Shelton.- Fclt by many. "Most building objects overturned. Motion slow; duration, damage was to chimneys-fell southwest. 30 seconds; moderate earth noises. Have heard of three cracked walls. Main Renron.-felt by all and frightened many return line broke on southwest side of my in community. At the Boeing Aircraft public pool. Objects displaced by jump­ l'lan t (reported hy Dr. Conlon B. Oake­ ing." Bumping motion in northwest to shou, California State Division of Mines south direction; gradual onset; roaring and Geology) , floors settled away from the earth noise heard at lime of shock. found.1tion piling: much interior concrete Skykomish.-Felt by and frightened all block cracked; fluoresce11t light fixtures in community. Damage slight to brick. down; acoustical ceiling tile fell, and con­ Chimneys fel l. Walls and chimneys crete tiles fell away from structural steel o-acked; plaster fell. Vases and small members. Press reported fireplace col­ objects overturned. Rapid motion in west­ lapsed, injuring tluee members of family. east or east-west d irection; duration, 30-45 Large boiler broke at the Pacific Car and seconds; moderate earth noises from west­ Foundry Company. Motion rapid; dura­ east. tion, 45-50 seconds; preceded few seconds Snoqualmie.-Felt by all and frightened by loud earth noises. many in community. Damage considerable Retsil.-Felt by all; awakened and to brick. Chimneys twisted and fell. frightened many in community. Damage Dishes and windows broke. Knickknacks, considerable. Chimneys twisted and fell. books, pictures, and plaster fell. Plaster, Dishes, windows, and furniture broke. windows, and chimneys cracked. Small Knickknacks, books, pictures, plaster, and objects and furnishings shifted; vases and walls (ell. Plaster, windows, walls, chim­ small objects overturned. Hanging objects neys, and ground cracked. Small objects swung northeast. Rapid motion in north­ and furnishings shifted; vases, small objects, east direction; duration, 30 seconds; mod­ and furniture overturned. Trees, bushes erate earth noises from northeast. shaken strongly_ Rapid motion in north­ Snoqualmie Falls.-Frightened many in south direction; moderate earth noises. community. Damage considerable. "Many Ronald.-Felt by all and frightened many chimneys and fireplaces down or not use­ in community. Damage slight to brick able." Walls, chimneys, Rues and fireplaces and masonry. Chimneys twisted and fell. cracked. Dishes and windows broke. Small Windows broke. Plaster and chimneys objects and furnishings shifted. Books out cracked. "Most damage confined to top­ 0£ bookshelves and bookcases; mail out of pled chimneys and broken windows." boxes and everything on floor at post office. Small objects and furnishings shifted; vases, Slides on Mount Si. R apid, rolling motion small objects, and furniture overturned. in east-west direction; moderate earth noises Large rock dump started to slide and cave. from east west. " It was like being on ·a Rapid motion in south direction; duration, small boat on choppy water." 5-10 seconds; faint earth noises. South Bend.-Felt by all and frightened Roslyn.-Awakened and frightened many many. Damage slight. Chimneys twisted 109

48 United States Earthquakes, 1965 and fell; chimneys cracked. Knickknacks up 15 feet in places. A 2-story beach house fell. Small objects shifted; vases and small was demolished and trees were uprooted. objects overturned. Motion slow; duration, Fill dirt for a road slid down a IOO-foot 1 minute. bank. A nearby resident reported the South Colby.- Felt by and frightened all beach below the bank heaved in a wave­ in community. Damage considerable to like motion and rolled like a wave toward brick and masonry. Chimneys twisted and the bank. The beach close under the fell. Dishes ancl windows broke. Knick­ bank seemed to sink several feet. "The knacks, books, pictures, stock on store earthquake left a high beach, most of which shelves, and plaster fell. Plaster, windows, was washed out by the high tide." Ground walls, and chimneys cracked. Small objects cracked. Books and plaster fell. Trees and furnishings shifted; vases and small and bushes were shaken strongly. Rapid objects overturned. Hanging objects swung motion in northeast direction; duration, and fell. Rapid motion in north-south 40-50 seconds; preceded 5 seconds by mod­ direction; duration, 45 seconds; preceded erate earth noises from the east. about 1 seconds by loud earth noises. Tacoma.- Felt by and frightened all in Stanwood.-Felt by many in community. community. Damage considerable. Press "One of the heaviest shocks ever felt in this reported the Union Station was evacuated locality." Damage slight. Chimneys due to extensive damage. Hugh chunks of twisted and fell; chimneys cracked. Knick­ concrete fell from the roof. No one was knacks, books, and pictures fell. Small injured, but most activity at the old depot objects and furniture shifted; vases and ,vas halted until damage could be deter­ smaJJ objects overturned. Moderate mo­ mined. Tacoma police said preliminary tion in northwest direction; duration, 20 reports indicated no major damage. About seconds. 60 windows were broken at Schoenfeld's Sultan.- Felt by and frightened all in Furniture Store, near the depot. Many community. Chimneys twisted and fell. walls and chimneys throughout the city Dishes and windows broke. Knickknacks, and suburbs were toppled; many windows books, pictures, plaster, and walls fell. shattered; gas and water mains broke. Plaster, walls, and chimneys cracked. Small Damage to schools was very light. One of objects and furnishings shifted; vases over­ the main downtown streets, Pacific Avenue, turned. Trees and bushes were shaken was littered with bricks and debris. A cross strongly. Pendulum clock stopped. Rapid fell from one church. The Narrows Bridge motion in east-west direction; duration, shook violently for 3-5 minutes, but no 35-45 seconds; preceded 3- 4 seconds by serious damage resulted. An official re­ loud earth noises. ported bolts on the bridge were sheared Sumner.- Felt by several and frightened and one light pole was down. A cashier few in community. Damage slight to at the toll plaza reported vibrating cables masonry.. Chimneys twisted and fell. Plas­ scarred concrete blocks, and that light ter and chimneys cracked. Small objects standards shook, dislodging glass fixtures. shifted. Rapid motion in east direction; All glass in the roadway lights was broken. duration, 45-60 seconds; moderate earth Cables rippled the length of the span. Two noises. liquor stores reported broken merchandise. Suquamish (about 15 miles northwest of Rapid motion in west direction; duration, Seattle) .- Felt by all; awakened and fright­ I minute; loud earth noises. ened many in community. Damage slight. Tahuya.-Felt by alt Damage slight to The press reported the shoreline of Suqua­ concrete. Chimneys twisted and fell. mish, in northeast Kitsap County, heaved Ground cracked. 5mall objects and fur- 110

Summary of Eartflquahe R eports 49

nishings shifted; china closet nearly over­ south direction; duration, 45 seconds; mod­ turned. Trees and bushes shook strongly. erate earth noises from north-south. Hanging objects swung north-south. Rapid NOTE: Since additional data have been motion in north-south direction, duration, received subsequent to the printing of the less than 1 minute; preceded 2-3 seconds by report, " The Puget Sound, Washington loud earth noises. "This earthquake was Earthqualte of April 29, 1965," some towns much stronger than the 1949 shock." that were listed in the report at lower in­ Tumwater (about 2 miles south of tensities have been re-evaluated at higher Olympia) .-Landslide caused breakage of intensities. · a sewer line and railroad tracks. The INTENSITY v1: Aclna, Alder, Algona, Union Pacific Railroad reported that a Aloha, Amanda Park, Amboy, American hillside fill slid away from beneath a 400- River, Anderson Island (47°09.8' north, foot section of a branch line just outside 122°42.0' west), Ardenvior, Arlington, of Olympia (press). Damage was esti­ Bainbridge Island, Baring, Bay Center, mated at about $200,000. Beaver, Belfair, Bellevue, Blaine, Bothell, Vashon lsland.-Considerable chimney Bremerton, Bridgeport, Brooklyn, Brush loss, wall cracks, and fallen plaster were Prairie, Bucoda, Burien, Burley, Burling­ reported from practically all parts of the ton, Burton, Carbonado, Cashmere, Castle island. The southern and western sections Rock, Cathlamet, Centralia, Chehalis, seemed to have been most severely Chelan, Chelan Falls, Cinebar, Clallam damaged. Press reports stated the Burton­ Bay, Clearlake, Cle Elum, Clinton, Con­ T ahlequah Road settled. Stock was thrown crete, Conway, Copalis Beach, Copalis from shelves in markets and bottles broke. Crossing, Cosmopolis, Cougar, Coupeville, Home waterpipe broke. Felt very strongly Darrington, Dryden, Dupont, Easton, at Vashon. At Ellisport, east shore, the Edmonds, Ellensburg, Elma, Ethel, Fall shock was felt by all, awakened few, and City, Fort Steilacoom, Fox Island, Frances, frightened many. Trees and bushes were Freeland, Galvin, Gig Harbor, Glenoma, shaken strongly; hanging objects swung Gooseprairie, Graham, Hadlock, Hansville, northeast. Rapid motion in northeast Harper, Hoodsport, H yak, Ilwaco, Index, direction; duration, 30 seconds to I minute; Indianola, Joyce, Kelso, Keyport, Kosmos, loud ea. th noises. La Center, Lacey, La Conner, Langley, Vaughn.-Felt by, awakened, and fright­ Lebam, Lester, Lilliwaup, Littlerock, Long ened many. Damage slight. Chimneys Beach, Longview, Lowel1, Lyman, Lynden, twisted and fell; some chimneys cracked. McKenna, Marblemount, Marysvi11e, May­ Knickknacks, books, and pictures fell. field, Medina, Menlo, Mercer Island, Mid­ Trees and bushes were shaken strongly. way, Monroe, Morton, Mossyrock, Mount­ Slow motion in west-east direction; dura­ lake Terrace, Mount Rainier National tion, 45 seconds. This was preceded by Park, Mount Vernon, Mukilteo, Naches, loud earth noises from the south. Nahcotta, Napevine, Nooksack, Nordland, Omak, Onalaska, Orondo, Oysterville, Wauna.-Felt by all and frightened many Pacific Beach, Packwood, Pe Ell, Porter, in community. Damage considerable to Port Gamble, Port Ludlow, Potlatch, brick and masonry. Chimneys twisted and Rainer, Randle, Raymond, Redmond, fell. Knickknacks, books, and pictures fell. R edondo, Richmond Beach, Rochester, Plaster, walls, and chimneys cracked. Small Rollingbay, R oy, Ryderwood, Satsop, Sea­ objects shifted and overturned. Trees and beck, Seahurst, Seattle Heights, Sekiu, bushes were shaken strongly. Pendulum Selah, Selleck, Shelton, Silvana, Skamokawa, clock stopped. Rapid motion in north- Snohomish, South Cle Elum, South Prairie, 111

50 United States Eartl,quakes, 1965

Southworth, Startup, Stevens Pass (Mount INTENSITY V IN OREGON: Aloha, Beaver, Persis region), Swift Dam (about 5% miles Brightwood, Cannon Beach, Cape Meares east of Cougar), Tokeland, Toledo, Toutle, Lighthouse (about 8 miles northwest of Tracyton, Tukwila, Union, Vader, Wilke­ Tillamook), Fairview, Gales Creek, Hebo, son, Winlock, \i\Toodinville, Woodland, Hillsboro, Jewell , McMinnville, Mayville and Zenith. (3 miles east of) , Milwaukie, Monmouth, INTENSITY Vl lN OREGON: Astoria, Birken­ Mosier (2 miles southeast of) , Mount feld, Boring, Buxton, Clatskanie, Clifton, Hood, Odell, Philomath, Portland, Rainier, Hammond, Knappa, Newberg, Seaside, and Sandy, Scappoose, Tidewater, Tigard, Vernonia. Timber, Tygh Valley, Valsetz, Warrenton, INTENSITY VI IN URlTISH COLUMBIA, CANADA: and Willamina. Victoria.-Plaster cracked; china broke. INTENSITY V IN BRITISH COLUMBIA, CANADA: Many vacated houses. Piles shifted at the Abbotslonl, Grand Forks, and Huntingdon. harbor. (Questionnaire canvass by Dr. 1N1ENS1TY IV IN WASHINGTON: Addy, Air­ W. G. Milne, Dominion Astrophysical way Heights, Albion, Almira, Anacortes, Observatory, Victoria, B. C.) Azwell, Bellingham, Benton City, Beverly, L'ffENSITY V IN WASHINGTON: Aberdeen, Bingen, Boyds, Brownstown, Camas, Carl­ Acme, Aeneas, Ajlune,. Ariel, Ashford, Big ton, Chattaroy, Cheney, Clayton, Chima­ Lake (about 6 miles southeast of Mount cum, Colbert, Colville, Conconully, CouJee Vernon), Blanchard, Bow, Brewster City, Coulee Dam, Cusick, Douglas, Edwall, Buena, Bumping Lake, Carlsborg, Carrolls, Elberton, Elmer City, Ewan, Fairfield, Forks, Chewelah, Chinook, Cliffdell, Colfax, Con­ Four Lakes, Fruitland, Grand Coulee, nell, Cook, Cowiche, Creston, Crewport, Granger, Harrah, Hartline, Hatton, Curlew, Curtis, Custer, Decatur Island, Hunters, Husum, Ione, lrby (about 10 Deep River, Deer Harbor, Deming, Doty, miles northwest of Odessa) , Kahlotus, East Olympia, Eastsound, Edison, Electric Kiona, Lamona, Lancaster, Laurel, Laurier, City, Everson, Ferndale, Ford, Friday Lincoln, Lind, Loomis, Lyle, Mabton, Harbor, Gardiner, Gifford, Glenwood, Malden, Malo, Manson, Marcus, Marlin, Grayland, Grays River, Greenbank. Marshall, Maryhill, Medical Lake, Mohler, Hamilton, Heisson, Hoquiam, Humptulips, Molson (10 miles south of, on Dry Gulch Inchelium area, Kalama, Keller, Kittitas, Road), Moses Lake, Northport, Odessa, Lakewood, Lamont, La Push, Loon Lake, Oroville, Othello, Outlook, Palisades, Pasco, Lopez, Lummi Island, Lynnwood, Malaga, Pateros, Point Roberts, Pullman, Rich­ Malone, Malott, Maple Falls, Marietta, land (Hanford Project) , Roosevelt, Sap­ Matlock, Mazama, Metaline, Methow, M.ill­ pho, Schwarder (5 miles south of Yakima), wood, Moclips, Monitor, Moxee City, Sequim, Spokane, Steptoe, Stratford, Sunny­ Naselle, Neah Bay, Neilton, Nespelem, side, Synarep, Thornton, Tiger, Tonasket, North Bonneville, Oak Harbor, Ocean Touchet, Trout Lake, Twisp, Union Gap, City; Ocean Park, Olga, Orcas, Port Uniontown, Usk, Valley, Veradale, Walla Angeles, Port Townsend, Prosser, River­ Walla and vicinity, Wa.rden, Washougal, side, Rock Island, Rockport, Rosburg, Washtucna, Waterville, Waukon, Wena­ Salkum, Shaw Island, Silver Creek, Silver­ tchee, Westport, White Swan, Wilbur, dale, Silverlake, Steilacoom, Stevenson, Wilson, and Yacolt. Sumas, Tenino, Thorp, Tumtum, Under­ I NTENSITY IV IN OREGON: Arlington, wood, Vancouver, Vantage, Waldron, Aurora, Bonneville, Cascade Locks, Cherry White Salmon, Wiley City, Winthrop, Grove (7 miles west of Gaston), Coos Bay, Withrow, Yakima (and 6 miles north of at Dallas, Depoe Bay, Detroit (Detroit Ranger Gleed), Yelm, and Zillah. Station, l miles west of Detroit) , Estacada, 112

S1111wwry of li.arlf1q11a/;e Reports 51

Gardiner, Caston, Gearhart, Goble. Springs. Kalispell, Noxon, Trout Creek, Government Camp, Hood River, Idanha, an< l Whitefish (5 V2 miles west of Bissel Ione, Lebanon, l'vJapleton, Marquam, Mill community). City, l\1 ulino, Nehalem, North Powder, INTENSITY 1-111 IN BRITISH COLUMBIA, CAF'i­ Oregon City, Pacific City, Parkdale, Prine­ ADA: Bowser, Castlegar (west side of ville, Rufus, Salem, Scottsburg, Shedd, Columbia River), Denman Island (west­ Sheridan, Sublimity, Tillamook, Walton, central section), Gabriola (Gabriola Island, '"'estlake, \\'est Linn, and vVoodbum. nonhwest section) . North Bend, Parksville, INTENSITY IV IN lOAHO: Athol, Bonners Pemberton, P1·inceton, Ucluelet, and Union Ferry, Bovill, Coeur D'Alene, Elk River, Bay. Moscow, 'onlman, Potlatch, anFarmer, Freeman, about 76 km. \\'. Magnitude 5.3. Felt Glenwood, Goldendale, Grandview, Kettle at Homer. Falls, Kewa, Larson Air Force Base (about January 3: 17:41:23•. Epicenter 59.9° 8 miles north by west of Moses Lake) , north, 153.6° west, southern Alaska, depth Liberty Lake, Locke, Mansfield, Mead, about 76 km, \\'. i\Jagniwde S.:l. Felt Mica, Metaline Falls, Nine Mile Falls, at Homer. Okanogan, Orient, Otis Orchards, Pine January 6: 08:27:36.0•. Epicenter 60.1° City, Reardan, Rice, Rosalia (5 miles north nonh, 15 1.8 ° west, Kenai Peninsula, depth and west of), Saint John, Soap Lake, Snake about 93 km, W. Magnitude 5.6. Felt River (5 miles north of), Springdale, at Homer. Tekoa, Toppenish, Urban (Sinclair January 6: 20:23. Felt at Homer. Island), Waitsburg, Wallula, Wapato, January27: 11:12. FeltonAdak. ,,vawawai (7 miles north of, on Snake February 3: (I) 19:01:21.8•; (2) 21: River) , Wellpinit, Winchester, Winona, 40:27•. Epicenter (1) 51.3° north, 178.6° and Wishram. east, Rat Islands, Aleutian Islands, depth INTENSITY I-Ill IN OREGON: Clackamas, about 40 km, W. Magnitude 7%, P; (2) Coquille, Culver, Eugene (Mahlon Sweet 50.9° north, 177.7° east, Rat Islands, Aleu­ Field, about 8 mile;; north-northwest of tian Islands, depth about 33 km, W. Mag­ Eugene), Florence, Fossil, Gresham, Halsey, nitude 5.0, W. VI. Buildings cracked Saint Helens, Silverton, The Dalles (4 or 5 and objects fell on Adak and Shemya miles west .of), Toledo. Waldport, Win­ Islands. Hairline cracks appeared in run­ chester Bay, and Yachats. ways on Attu. The first shock generated INTENSITY 1- 111 IN ID.AHO: Calder, Coolin, a tsunami that was recorded at several Dover, Harrison, Kootenai, and Sandpoint. tide stations (see ''Tidal Disturbances of INTENSITY I- III IN MONTANA: Hot Seismic Origin,'' page 6 I) . Slight Hood- 113

SELECTED REFERENCES

Edwards, H. H., 1950, Discussion of damage caused by the Pacific Northwest earthquake of April 13, 1949, and recommendations of measures to reduce pro­ perty damage and public hazards due to future earthquakes: (report to) Seattle Section, American Society of Civil Engineers, 30 p.

The report is essentially the same as the three articles published in "Western Construction" that are reprinted herein.

Hopper, M. G., and others, 1975, A study of eart hquake losses in the Puget Sound, Washington, area: U.S. Geological Survey Open File Report 75-375, 298 p.

A study • intended to inform those agencies ••• of potential hazard to people, structures, and lifeline functions• to facilitate "planning response to earthquake disaster.• Simulates two 7 . 5-magnitude events and what their effects might be in Snohomish, King, Pierce, Kitsap, and Mason Counties.

MacPherson, S. H., (1965), A report of the April 29, 1965 earthquake, Seattle, Washington: Seattle Fire Department, 21 p.

A report about bu i lding inspections in Seattle, with five photographs.

Rasmussen , N. H., and others, (1974), Earthquake hazard evaluation of the Puget Sound region, Wash ington State: Geophysics Program, University of Washington, Seattle, 99 p.

General report that attempts to project damage from future quakes. Includes epicenter maps and list of damaging quakes. Essentially technical; no photographs.

U .s. Army Corps of Engineers, 1949, Report on damage resulting from earth­ quake of 13 April 1949: Seattle District, 27 p.

An internal, rather detailed report with five photographs, appendicf' about "soil and foundation rupture", and a list of damage to the Northf' Pacific Railway . A

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