THREAT TO' PORT ALBERNI

Prepared for

Allan M. McCrae Consulting Civil Engineer Victoria, B.C.

and

Reid,.. Crowther- & Partners Limited Consulting Engineers and Planners , B.C.

I I i i

by

Sydney o. Wigen, P.Eng. 4053 Nelthorpe Street Victoria, B.C.

February 1977 Contents Page Abstact 5 Alternative Approaches 6 Numerical For~casting 6 Historical Forecasting 7 Source Data 7 Data Extraction 8 Port Alberni - Relationship 10 Tsunami Hazard, by Zone of Or~gin 12 Tsunami Frequency at Tofino and Port Alberni 15 Characteristics of the 1964 Tsunami at Port A1berni 19 Contribution of Tide to at Port A1berni 21 Tsunami Threat to Lugrin- Creek Site 21 Mitigation of Tsunami Damage 22 Acknowledgement 22 Ref.er.enc.es 23 Appendix: A 25

-~ Illustrations and Tables Page Figure 1 Tsunami wave heights 10

Figure 2 Alaska - Aleutian Islands. epicenters and magnitudes; and maximum tsunami wave 'produced at Tofino. 16

Figure 3 Kamchatka Peninsula, Kuril Islands, and Japan. Earthquake epicenters and magnitudes, and max.lmumct sunamj, ',wave produced at Tofino.· 17

Figure 4 Number of tsunamis recorded at Tofino, ,with maximum. wave equal or larger than value'give in ordinate. 18

Figl.-rre'- 5 Tsunami of March 27, 1964 as recorded' at -Tofino and Port Alberni. 20

Table 1 .Summary of studied, and tsunamis identified at Tofino and Port Alberni. 9

Table·-2 Maximum tsunami waves at Tofino and Port Alberni. II

/

\ .. 5

Abstract

A historical approach has been undertaken in this report to evaluate the threat of tsunamis to Port Alberni. From catalogues of tsunamis, a list was compiled by area of more than 100 major tsunamigenic events occurring throughout the Pacific since 1900. Availab~eTofino and Port Alberni analogue tide records were studied to find evidence of the waves reaching the Coast. Twenty-one of 70 events examined showed a tsunami at 'I'ofLno, and 5 of 19 at Port Alberni.

The size of maximum tsunami waves at Port Alberni was found to b~approximately double that at Tofino, where both stations had' recoTded the same tsunami. It was concluded that Tofino records. could..be used to estimate the. frequency of tsunamis at Port Alberni, and the probable maximum waves that would have been recorded•

.;., '~..- . Of' the 21 tsunamis known·to have reached the coast, 15 came from:::the region ,between Gulf of Alaska and northern Japan. In the half century of records studied, the 1964'tsunami was.highly destructive in ; the 1960 event was moderately damaging;. and 3~more...tsunamis may have been close to the point of doing damage.

In designing for a one-in-200 year event in Port Alberni, at least one tsunami of the 1964 size must be anticipated. TSUNAMI THREAT TO PORT ALBEmTI

Alternative Approaches'to Forecasting. Tsunami Hazard

~vo alternative procedures·canbe·applied to forecast the runup of tsunamis in Alberni Inlet, one numerical, and the other hist.o'r.Lca.L,

Numerical Forecasting

A hydrodynamic numerical modelof'Albernilnlet and approaches would be developed. The accuracy of the model would be calibrated by· applying normal· tides at the entrance to.the model, and COIDp-ar±n.g simulated tides .produced·at check points in the model . . agains-t. those occur-r.tng dn the prototype., Simulated ·.tsunamis from various· sources in the Pacific Ocean could ·then ·beapplied to the mo de'l-centrranee., and ·the response at the head" of the Inlet, or at any-other location within the model could.be calculated.

Numerical forecasting has the advantage that as many different· source conditions as required may be tested, and the probable most criticaLevents may vbe determined. However, scientists engaged in this type of·study·advise that the·investigation of a waterway as complex as Alberni Inlet and would probably require at least six months ·of research time. The cost of such a study, including computer support, appears to be prohibitive for Lugrin Creek planning, but might be feasible as a research project correlated with overall planning for the head of Alberni Inlet.

A limitation of the numerical modelling technique must be recognized, that the precise nature of the delta area becomes critical in the Tunup interpretation. Simu~ated response of the model might be changed significantly by slight changes in the assumptions regarding the delta. 7

Historical Forecasting .

The historical approach requires a review of tsunamis known to have occurred thr~ughout the Pacific Ocean. Records and publications are examined to find which of these tsunamis reached' the" coast. For a study of Albemi Inlet and approaches~ the principal rec­ ords are the analogue diagrams from tide gauge s~ations at Port Alberni and Tofino. From such a study it becomes possible to identify which zones of the Pacific represent a potential tsunami source~ and to make some estimate of the frequency with which tsunamis may reach the Coast. Such a study has been undertaken for .this report, and from the data col­ lected and summarized we can draw some conclusions on the tsunami threat to Port Alberni.

Source.. Data

For this study, available catalogues of tsunamis at the Inter­ nationaL'Tsunami Information Center in Honolulu were reviewed. More than.lOO earthqu~kes with Richter magnitudes between·7.5 and 8.6, oCcur­ ring since 2900 were tabulated by" area. Some known exceptionally large earthquakes of earlier years were also listed. Approximate travel times for:waves from each epicenter to reach Tofino or Port Alberni were ex­ tracted.from tsunami travel time· charts.

Through the co-operation of the Tidal and Current Section, Canadian

Service~ Hydrographic Service t in Victoria, and Marine Environment Data Ottawa~ analogue tide gauge records from Tofino and Port Alberni were made available. The records were scanned at the estimated arrival times~ and any evidence of a tsunami was listed. Port Alberni original gauge records were available from 1963 to 1976~ but with interruptions. The Tofino tide gauge has been operated fairly continuously by the Government of since 1906, and for most of. these years~ the original records were also available. However, there are some years of Tofino tide 8 records that now exist only on microfilm, and only a few prints from these records have been available in time for use in the preparation of this report.

Detail on the original records is sufficiently clear that generally a tsunami registering a wave of 2 em or more at Tofino can be identified. On the m~crofilm, whether similar tsunami oscillations can be recognized is dependent on the quality of the' original record.

Data Extraction

Appendix A contains a listi;ng of the' tsunamigenic events of the past' century that was prepared for this s tudy, grouped: by areas, the

Richter magnitude of the earthquake, and its depth of focus in kilometerss where-available. The arrival time of the initial wave at Tofino and its height in centimeters is listed, followed by R or Fto indicate whether the wave was rising or EaLl.Lng; The time of commencement and height of th~~um wave for each tsunami, as recorded at Tofino, is also listed. AlL_t±mes are gi~en in Universal Time (U.T.). A similar extraction of tsunamis was made for Port Alberni. Table 1 summarizes the number of events' by area and by magnitude, the number of these for which tide r ecozds were available for scannfng, and the number of tsunamis identi­ fied on 'Tofino and Port Alberni tide diagrams~ Twenty-one of 70 events showed a tsunami at Tofino, and 5 of 19 at Port Alberni.

In past tsunami data extraction it has been cornman practice to measure the height of a wave f;rom trough to crest, with the inf~uence of the tide included. For this study, intercomparison of the 'waves at Tofino and Port Alberni was required, so the contribution of the tide has been deleted. This has been done by measuring each trough or crest as the maximum displacement from an assumed tide that would have occurred had there been no tsunami. Tidal Records Scanned and Number of Events by Magnitude Visible Tsunami Identified

Area >7.9 7.5-7.9 <7.5 UnknoWn Total Tofino Port Alberni

1. Chile - Peru 4 10 2 16 8/2 5/0

2. Ecuador - Mexico 2- 8 1 11 7/0 I/O 3. Baja California - Alaska Peninsula 2 .1 3 6· 3/0 1/0

4. Gulf of Alaska - Aleutians 1 3 10 6/5. 3/1

5. Kamch~tka - Kurils 7 3 ·1 11 9/7 4/2

6. Mariana - Japan Trench 4 9 13 10/3 2/1

7. .Ryukyu - Philippine Trench 5 8 13 9/0 2/0

8. S. China - Sulu - Celebes Sea 3 3 6 3/0 0/0

9. Java Trench - Banda Sea 1 3 1 5 3/0 a/a

10. N. Guinea - Bismarck Archipelago 2 2· 1/0 .0/0

II. Solomon Sea - New Hebrides 4 9 13 6/1 0/0

12. Tasman Sea 2 2 2/0 0/0

13. Kermadec - Tonga Trench '4 1 5 2/2 a/a

14. Hawaii i 1 1/1 1/1 .43 59 9 3 114 70/21 19/5

Table 1. Summary' of earthquakes studied,. and tsunamis identified at tofino and Port Albern!

'. 10

In a typical case, as shown in Figure 1, the y height of the initial wave I is taken as X-B, and not I X-A. Similarly the maximum I wave is not Y-Z, but (Y-~) r : + (D-Z). ei

(Right) Figure 1. z Tsunami Wave Heights

Port Alberni - Tofino Relationship

To establish the frequency and hazard of tsunamis at Port Alberni from...the very limited data would require an extrapolation that would have little validity. However, Tofi~o, only "lOO kilometers ~way, offers a much longer-history. The question comes up of whether. the response of the two ports-·-is sufficiently similar that one can make any assumptions about tsu­ namfs.cat; Port .AJ.berni from those recorded at Tofino. Although the char­ acteristics of the waves are markedly different, we can attempt a correla­ tion of the maximum waves of tsunamis observed at both locations. The first comparison ~s for the 1960 tsunami from Chile which produced the Lar-gestrwave ~ecorded to that time at Tofino. No gauge wa? operat.Lng at Port Alberni, but the waves were reported to be large enough. to damage log booms; one rise of about 2 meters was described at the paper loading dock; and offices at MacMillan Bloedel Limited were sufficiently con­ cerned that the Company agreed to co-operate with the Canadian Hydro­ graphic Service in the installation and.operation of a pennanent tidal station, principally to have its records available in the possible event of a future tsunami. I This fortuitous decision has made possible the data for this study, and even though the disastrous 1964 tsunami did exceed the gauge range 11

and put it out of action briefly, the record none-the-less has been invaluable.

Subsequent to 1960, five tsunamis were registered on both the Tofino and Port Alberni tide gauges. Table 2 gives a comparison of the maximum waves for which recorded or estimated h~ights can b~ given.

MaximUm Wave Maximum Wave Date Tsunami Source Magnitude Tofino " Port Alberni

May 22, 1960 Chile 8.5 126 200 (estimate) Oct 13, 1963 S. Kuril Is. 8.2 16 27 Mar 28, 1964 Alaska 8.4 240 800 (estimate) May l6, 1968 N. Japan 8.2 12 24 AugIl., 1969 S. Kuril Is. 7.8 6 4 Nov 29, 1975 Hawaii 7.2 9 10

--Tab.le 2.. Maximum Tsunami Waves at Tofino and Port Alberni

For the larger tsunamis there is a reasonable correlation between the-,::two ports, with the maximum at Port Alberni averaging ab-out twice the~"height" of the maximum at Tofino. In addition there were several examples of both ports having no response to "a tsunami~ and no occasion onrecord:when one responsed and the other did not.

On the strength of this evidence we conclude that the frequency of tsunamis occurring at Tofino from various sources establishes the fre­ quency for Port Alberni, but "that larger size waves must be expected at Port Alberni than Tofino for major events. 12

Tsunami Hazard, by Zone of Origin

Less than one hundred years of systematic seismic and tidal records are available for tsunami studies. Regi~nswith tsunamQgenic potential may exist in the Pacific that have produced no major earth­ quakes in the past century. Understanding of the plate tectonic move­ ments producing most of these earthquakes is very recent. It is not known whether seismic zones are alternately active and quiescent 'over decades or centuries, or whether the frequency of earthquakes and tsunamis is fairly constant. Of necessity then the history of activ­ ity during the past century becomes the' criterion we must use to estimate future threat.

Peru-Chile Trench

Tofino.tide'records were available for 8 major earthquakes of the past 60 years. Only 2 showed evidence of a. t.sunami., but one' of these~ in 1960, was the second largest wave registered at'Tofino. The tsunami from this earthquake was one of the most severe on record in the Pacific, and caused severe damage and casualties in South.America, Hawaii, and Japan.

Ecuador-Nexico

The subduction zone of the Middle America Trench has produced a number of tsunamis, but these appeal:" to be directed away from the Canadian west coast. Tofino tide records showed no 'evidence 'of tsunamis resulting from any of seven earthquakes in this areae

Baja California - Alaska Panhandle

Earthquake movements tend to be strike slip, having hori­ zontal rather than vertical displacement, and therefore, are generally non~tsunamigenic. Two records examined showed no tsunami. 13

The most recent of these, with~a magnitude of 6.7, occurred on Dec. 20, 1976, 200 kilometers west of Tofino. A subduction zone lies off and Wash~ngton, associated with local sea floor spre~dingo The Earth Physics Branch of Energy, }lines' and Re­ sources Canada does not rule out the possibility of a tsunami from this source, but indicates that if any occur here they are suffi­ ciently rare that the last wa~ generated before the time of recorded history on the Coast.

Gulf of Alaska~Aleutian'Islands

Five of six large earthquakes'produced'tsunamis at Tofino; two additional earthquakes in the western Aleutians, for which Port Alberni but not Tofino records were available,' did not. The 1964 earthquake, near Anchor.age,'produced the'l~rgest' tsunami on record at Tofino and Port Alberni.

Kamchatka Peninsu1a~Kuti1 'Islands

Of nine events examined seven earthquakes produced tsunamis at Tofino. Of these, the magnitude 8.2 earthquake off Kamchatka regis­ tered the largest maximum wave at ,Tofino from this area, 58 em.

Mariana-Japan Trench

Tofino tide records were available for the time of 10 major earthquakes, and of these 3 showed tsunamis. Epicenters of these were all ,off Hokkaido and northern Ronshu~ The largest maximum wave at Tofino from this area, of 23 em, was produced by the Great Showa Sanriku Tsunami of 1933, that killed thousands of people in Japan. 14 Ryukyu Trench-New Guinea

In areas 7 - lO.on Table 1, from southern Honshu to the Philippines, Indonesia and New Guinea, Tofino records were examined for 16 earthquakes, and none of these showed evidence ofa tsunami.

Solomon Sea-New Hebrides .

One earthquake on the northeast shore of the Solomon.Islands produced a 6 em maximum Wave at Tofino. No other tsunamis from this area showed on the records examined.

Tasman Sea

Two records examined showed no evidence of a tsunami at Tofino•.

Kermadec-Tonga Trench

-~¥o earthquakes studied, of magnitudes 8.0 and 8.3, generated tsunamis at Tofino with maximum waves of 12 and 9 em respectively.

Generally, the southwest Pacific would appear from the foregoing results, and from the location of tsunami generating areas relative to Tofino and to intervening island arcs, to offer no significant tsunami threat to the .

Hawaii

The magnitude 7.2 earthquake of November 1975 is the only tsunamigenic event from this area on record at Tofino. It registered a maximum wave of 9 em. The previous significant earthquake in Hawaii occurred in 1868. Whether a major Pacific-wide tsunami could originate from this area is unknown. 15

Tsunami Frequency at Tofino and Port Alberni

The region from Gulf of Alaska.to Japan, areas 4,5, and 6 in Table 1, clearly provides the most significant tsunami threat to Port Alberni. At least 34 tsunamigenic earthquakes occ.urred in 80 years, and of' 25 of these for which' Tofino tide records wexe avail­ able at :the time of the study, 15 sho'i1 clear evidence of a tsunami. ·Locations of epicenters for this region are shown on Figures 2 and 3. With 'each-is shown the magnitude of the earthquake, and the height of the maximum wave generated at Tofino from the event. Eighteen of the earthquakes from the region registered a magnitude . - of 8.0 or larger, a size for whichaPaeific-wide tsunami warning is autqmatically issued from the Honolulu Observatory.

In the. p~riod of record'. six tsunamis reached Tofino from the rest of the Pacific, the one in 1960 being-large enough to cause damage. Figure 4 shows the number of tsunamis recorded at Tofino , with maximum wave height larger than any given value. Plotted logarithmically, the result is approximately ·linear. The signifi­ cance of this relationship is not clear, _since the sample is an in­ complete record of the number of tsunamigenic events_that occurred, and_furthermore, .it groups all tsunamis regardless of the area of origin•.

Seismologists who have studied. earthquake frequencies, and who were queried during the preparation of this report·, warned _against . . attempting to extrapolate .tsunami frequencies from the presently known history. In particular they cautioned .against identifying the frequency with which the rlisastrous tsunami of 1964 would be equalled or .exceeded. It was felt that mathematical expressions of probability and frequency_ had little relevance to the data, since the mechanisms producing tsunamis, or focusing their direction of travel from sourc.e are not well understood. : z»

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Figure 3. Kamchatka Peninsula, Kuril Islands and Japan Earthquake Epicenters and Magnitudes, and Haximum Tsunami Wave Produced at Tofino 18

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Figure 4. Number of tsunamis recorded at Tofino, with maximum wave equal or larger than value given in ordinate. 19

Notwithstanding the validity of this point of view, some con- ,- elusion on tsunami hazard is a specified requirement of the Lugrin Creek Study, and the material here compiled is the most comprehen­ sive set of data on tsunami impact on Tofino and Alberni Inlet yet assembled. From these data it is apparent that tsunamis reaching the British Columbia coast, and specifically Alberni Inlet, are a much mor.e common phenomenon than had generally been recognized. In the past half century, one tsunami has been highiy destructive, and another moderately damaging. Assuming an amplification on waves recorded at, Tofino,as evidenced by the data in Table 2, 'three more tsunamis in this same period may have been close to the'point of being moderately damaging. Earlier tide records back to 1906, may give some further indication on tsunami freque~cies when the micro­ films are studied. Newspapers prior to .-1906 may also provide in­ formatri.on if events comparable, to the 1964 tsunami occurred subse­ quent to the development of Alberni as a port~

On ~resent knowledge, for a design criterion based 'on a one in 200 year event, at'least one tsunami of the 1964 size must be expected.

Characteristics of the 1964 Tsunami at Port A1berni

Figure 5 (taken from Marine Sciences Directorate ~illnuscript Re­ port Series, No. 36)" shows the analogue trace of 'the 1964 tsunami at Tofino and Port Al.be'rnd., For the first 8 hours the 'Port Alberni gauge was for the most part out of service, and waves exceeded the range of the gauge. However, parts of the first and second rise were recorned, and the maximum crest was identified with accuracy by the water level mark on the gauge house wall, at 20.9 feet (6.4 m). The first three crests were recorded also on the Soroass River gauge, and helped in recreating some of the missing record. The second or maximum crest reached an elevation of 19.6 feet (5.6 m) on the gauge, showing a drop in tsunami height beyond the end of the harbour. TSUNA~I WEST COAST OF CANADA MARCH 27 -29 1964 20 U \0 12 ,~ ..I. '? \3 20 22 0 4 10 , eure lIJoIfitUg TI I

~ .k. ~ I ~ \ - "' ..111 -, V \:;fr4 J tI V ,If \ I _. ~\ - \, , II r~ -~ K I - i .:.- - -. il ,~ -~ - :lJ i IJ rr I til ;\ if) .i.~ \ rJJ 1/ / I J , , i J I ~ I~ r! fr - ~V \ '-ci'# l ';/ :,lv l· ~M 1\lrvII n I

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QllI(ljMO' IJ 10 P 1" 111 111 20 :u f1lll..Wf,T'"0 • 10 12 1'" tS 13 31 Figure 5. Tsunami of March 27, 1964 as recorded at Tofino and Port Alberni 21

Of the 5 tsunamis at Port Alberni for which analogue records . . are available only the 1964 event shows dominant waves with a period of about 90 minutes. This is also the apparent period of a natural seiche in the Inlet, and corresponds closely with one of the natural frequencies of Alberni Inlet calculated. by Murty and Henry (1972).

Contribut:Lon of Tide to Tsunamis at Port Alberni

In the 1964 tsunami the first waves came in vThen the tide was cresting at about 10 feet (3.0. in), very close to the 10.4 feet (3.2 m) level of higher high water mean tide.;

Since the elevation of higher high water, large tide is 12.2 feet (3.7m) and the all time extreme tide (non tsunamis) is 14.3 feet (4.4m), in a once in 200 years tsunami the prospect of a higher tide contributing substantially to a tsunami flood crest is small. It is more likely that a minor variation in the s t rengfh of inlet response to a.particular tsunami would have more impact than tide on the flood crest ·reached.

Tsunami Threat to the Lugrin Creek Site

Unless exceptionally high dikes can be provided. in any Lugrin Creek development, the possibility that a tsunami' will flood the area has to be accepted.

With the present capabilities of the Tsunami Warning System in the Pacific, and of Civil Defense authorities in Canada, it is probable that at least 2 hours warning of an impending tsunami can be given, and that evacuation of people ~ivin~, working, or enjoying recreational facilities in the area can be effected. This potential need for evac­ uation needs to be recognized in designing roads leading from the low lying ·area. The remote .threat of a severe tsunami generated near the coast probably does not warrant undue concern for the proposed Lugrin Creek development, but could be a significant factor in siting an atomic power plant, or major oil terminal in Port Alberni.

As an additional but hidden cost of development, periodic evac­ uation for tsunamis, that could, but do not actually flood the area must be anticipated. Such false alarm evacuations may be anticipated once per decade, or oftener, based on the history of tsunamis in the Pacific.

Mitigation of Tsunami Damage

Damage from tsunamis may result from flooding.when the water is raised to abnormal levels, and from the very strong currents asso­ ciated wi.th the rapid changes in water level. Dikes will be scoured, log booms destroyed, and vessels driven ashore.o!, overturned. Damage or destruction may occur from the dynamic pressures and pressure dif­ ferentials on the faces of structures, and by excessive'erosion of the foundations. Logs and floating debris become damaging or destruc­ tive missi.les.

Experience in parts of the Pacific has shown that trees, closely spaced, reduce some of these hazards. Retention or enhancement of :1 i I I natural vegetation should be encouraged during any development.·· :1 I I

,·1I Acknowledgement ! I I i Of many people who have advised or assisted with aspects of this .' study I would like to acknowledge in particular the support and interest '11 of G. Pararas-Carayannis and M. Ching, International Tsunami Information ., .1 Center; G. Miller (deceased) and H. Loomis, Joint Tsunami Research .,;'1 Effort; w. Rapatz and J. Manson, Tidal and Current Survey; G. Rogers, " Seismology and Geothermal Studies; R. Brazee, National Geophysical and j Solar-Terrestrial Data Center; and J. Derr and R. Kangas, National Earthquake Information Service. :1 23

References

Braddock, R.D. 1975. An analysis of the conventional tide well. Applied MathematicsPreprint No. 86, University of Queensland.

Cox, D.C. and George Pararas-Carayannis, with revisions by J.P. Cal.eb augh, 1976. Catalog of tsunamis in Alaska•. \lorld Data Center. A for Solid Earth Geophysics, Boulder.

Henry, R.F. and T.S. Nurty. 1972. Resonance periods of multi­ branched inlets with tsunami amplification. Marine Sciences Directorate Ottawa. Manuscript Report Series No. 28.

Iida, K. 1961. Nagnitude, energy, and generation mechanism of tsunamis, and catalogue of earthquakes associated with tsunamis. Tenth Pacific Science Congress.

Iida,_ K•., Doak C. Cox, and George Par-aras-Carayannf.s," 1967. Pre­ .Limfriaz'y catalog of tsUnamis occurring in the PacifiC. Ocean. Hawaii Institute of Geophysics, University of Hawaii.

Neyers., H.; R.J. Brazee, J.L. Coffman, and S.R. Lessig. 1976. An analysis of earthquake intensities and recurrence rates in and near Alaska. National Geophysical and Solar­ Terrestrial Data Center, Boulder. NOAA Technical Memorandmn EDS NGSDC-3.

Nurty, T.S. and L. Boilard. 1970. The tsunami in the Alberni Inlet caused by the Alaska earthquake of March 1964. Proceedings of the international symposium on tsunamis and tsunami research. Ed. W.N. Adams. East-West Center Press. Honolulu. p. 165-187. 24

Nurty, T. S. and R. F. Henry. 1972. Some tsunami studies for the west coast of Canada. Marine Sciences Directorate, Ottawa. Manuscript Report Series No. 28.

Murty" T~S., S.O. Wigen, and R. Chawla. 1975. Some featur.es of tsunamis on the Pacific coast of South and North America. Narine Sciences Directorate, Ottawa. Manuscript Report Series No. 36.

National Ocean Survey. 1971. Tsunami travel time charts. Na­ tional Ocean Survey, NOAA. Rockville,'Md.

Pararas-Carayannis, G. 1969., Catalog of tsunamis ,in the Hawaiian Islands. World Data'Center,-A Tsunami. U.S. 'Coast & Geodetic 'Survey.

Silgado ~. Enrique. 1974. Historia de los grarides tsunamis'pro­ ducidos en- la'costa occidental de America del Sur. Centro Regional de Sismologia para America del Sur. Lima. (in Spanish).

Soloviev,'S.'and Ch, N. Go. 1969. Catalog of tsunamis in the Pacific Ocean. Sakhalin Complex Scientific Research Institute. (in Russian)

Wigen, S.O. ,1960. Tsunami of May 22, 1960, west coast of Canada. Technical report, Marine- Sciences Branch.

Wigen, S.O. and W.R.H. l~ite. 1964. Tsunami of March 27-29; 19'64,. west coast of Canada. Department of Mines and Technical Surveys. Victoria. .;'"

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Appendix A

Tabulation. of earthquake epicenters, by area,

and tsunami waves registered 'at Tofino TRAVEL TIMES OF MAJOR TSUNAMIS

AREA OF ORIGIN: Chile ... Peru GkdGl~ SITE ~,ECORPEn:, Tofino i • ; ,. : J .' HOUR HRS FRON EST.AR. INIT.WAVE MAX. WAVE YEAR 1'10. DAY. (D. T.) LAT. LONG. }fAG. DEPTH GAUGE (U. T. ) ARR. HT. ARR. HT. PERIOD' COMMENTS 1868 Aug 13' 1645 l8S 7lW 1877 May 10 0059 21.55 ' 71W 1906 Aug 17 0040 338 72W 8.4 16 '1/2 1922 Nov 11 0433 28.58 70W 8.3 16 2033 2030 3R 12/0333 27F 1928 Dec 1 0406 358· 72W 8.0 16 '1/2 2036 No tsunami 1943 Apr 6 1607 31.58 71.4W 7.9 10 16 7/0807 No tsunami 1959 Feb 7 0937 48 81.5W 7.5 0 12 1/2 No record 1960 May 21 1003 37.58 73.5W 7.5 17 22/0303 No tsunami' 1960 May 22 1911 39.58 74.5W 8.. 5 17 23/1211 1221 22R 1730 126F 1966 Oct ,17 2142 10.7S 78.7ii1, 7.5 , 24 ,'13 1/2 ,No record 1966 Dec 28 0818 , 25.58 70. 7iii 7.6 32 ,16 ' No record r " , Dec 21 0225 21.7S 70.0W 7.5 15 1/2 .~ No tsunami 1967 - , 1970 Nay 31 2023 9.28 7S.aW ' 7.8 43 13' 1/2 No tsunami, 1971 July 9 0303 32.58 71.2W 7.5 58 16 1/2 No record, 1974 Oct 3 1421 11.58 nv. 7.7 13 13 1/2 No tsunami 1975 May 10 1428 38.13 73, •• 2W' 7.8 6 16 1/2 No tsunami

.\ '., TRAVEL TIMES OF MAJOR. TSUNAMIS

•' :' 'j , .' ~. I AREA OF ORIGIN: Ecuador - Mexico GAUGE SITE ~EPO~TJED;' _T_of_i_n_o _

HOUR ERS FROM ES~.ARt INIT.WAVE MAX.WAVE YEAR HO. DAY (~) -LAT. LONG. MAG~ DEPTH GAUGE .(U.T.) ARR. UT. ARR. HT. PERIOD COMMENTS 1906 Jan· 31 1536 IN 81.5W 8.6 12 1/2. 1928 June 17 0319 .16.2N 98W 7~8 '9 No tsunami 1932 June 3 1037 18.5N :.104.2W 8.1 7 1/2 No tsunami 1932 June 18 1012 IB.5N 103.5\>1 .7.8. 7 1/2 No tsunami 1934 July 18 0136 8N 82.5W. "7.7 12' No tsunanii 1941 Dec 5 2047 8.5N 83W 7.5 12 No record 1950 Oct 5. 1610 10.4N 85.7W 7.7 95 11 1/2 No record I 1953 Dec 12 1731 3.5S 81\>1 7.8 12 No record 1957 July 28 0840 16.5N 99.0W 7.9 8. 1/.2 No tsunami 1958 Jan 19 1407 1.5N 79.5W 7.4 60 12 1/2. No tsunami .,', 1973 Jan 30 2101 18.5N 103W . 7.5 . . 43 . a No tsunami

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TRAVEL TIMES OF MAJOR TSUNAMIS Baja California ­ AREA OF ORIGIN: Alaska Panhandle pAUG~ ST.tE R¥~d~~p;' ~To~f~i~n~o ~ ___

I HOUR fIRS VROH EST.AR. INIT.WAVE ' MAX.WAVE YEAR MO. DAY (U.T.) LAT. LONG. }-rAG. DEPTH GAUGE (U. T.) ARR. HT. ARR. HT. PERIOD' COMMENTS

1906 Apr 18 1312 38N 123W 8.25 3 1928 Feb 9 0304 49N ' 125W ',5.8' 1946 June 23 1713 49.8N 124.9W 7.3, ' 1949 Aug 22 0401 ,53.7N 133~2W, 8.1 1 1/2 No tsunami 1958 July 10 0615 , 58.6N 137.1W 7.9 3 No record 1976 Dec 20 2033 49.0N i28~8W '6.7 1 No tsunami TRAVEL TIMES OF MAJOR TSUNAMIS

.: .' I I. 1.,:,( • . AREA OF ORIGIN: 'Gulf of Alaska - Aleuttans GAUGE SItE RECq~p~D: T.;..;."o....,:f:..:;·i:..:;n:..:;o _

HOUR In~S FROM ~sT,AR. INrr.WAVE l-fAX.WAVE YEAR -,---MO. DAY (U.T.) LAT. LONG. MAG~ DEPt!! GAUGE /1], T.) ARR. HT. ARR. HT. PERIOD' COMMENTS 1$97 Sept 10 2140 60N 140W 8.6 . 1899 Sept 4 0022 60N ·142.3W 8. 1929. Mar 7 0134 51N l70W· 8.1 5 ... · 0634 06394F ,0800,llF 1938 Nov 10 2018 55.5N 158W 8.3 4 11/0030 001112R '0125 27F 1946 Apr. 1 1229 53.5N l63.0W 7.4 4 u: 1700 ·1650 21R '.20,52 58F 1957 Mar 9 1422 51.3N 17S.8W 8.3 6 2022 1907·14R1Q/013749R 147~7W ~9R' 1964 Mar 28 0336 61.1N , 8.4 33 4· 0736 . 0700 0850 240F 1965 Feb 4' 0501 51.3N 178.6E 8.2. :40 6 - No record 19'65 Mar· 30 0227 SO.6N 177.9E 7.3 51 6 1/2 No record 1975 Feb 2 0843 53.5N 173E 7.4. 10 '7' No tsunami

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, . TRAVEL TIMES OF MAJOR TSUNAMIS

AREA OF ORIGIN: . Kamch~tka .... Kuri1 Is~ GAUGE SITE RECO{¢kq: Tofino ,,'." ~=::;.::------HOURHRS FROM ~sr.AR, rNIT.WAVE MAX.WAVE YEAR 1'10. DAY CU. T•) LAT. LONG. HAG. DEPTH GAUGE (U. T•) ARR. HT. ARR. HT. PERIOD COMMENTS

1918 Sept 7 1716 45.5N 151. 5E. 8.2 ·9' 8/0216 014~ 9R. 0306 14F 1923 Feb 3 1602 54N 161E' 8.3 8 2400 2354 6R 4/0350 ZiF' 1923 Apr 13 1531 56N 162.5E 7.2 8' 2331 14/0027 9R 0806 15F 1952 Nov 4 1658 52.7N 160.3E. 8.2 33 8 5/0100 . 0042 21R 0347 58R 1958 Nov 6 2258 44.5N 148.5E 8.7 75 9 i/2 7/0830, 0807 9R 1655 10F 1959 May 4 0716 52.5N 159.5E· 8.0 60 No record 1963 Oct 13 0518 44.8N 149.~E. 8.2' 60 9 1418 "':' 3 1857 16F 1969 Aug 11 2127 43.5N 147.4E 7.8 28 9 1/2 12/0700 0630 2 6 1971 Dec 15 0830 56.0N 163.3E 7.8 33 No record 1973 Feb 28 0638 SIN 157E 7.6 27 8 1430 No tsunami 1973 June 17 0355 43.2N 145.8E 8.0' 48 9 1/2' '1325 No tsunami -TRAVEL TIMES- OF MAJOR TSUNAMIS .. r • . ' I:.~ I, .' ,; ( I MEA OF ORIGIN: _l1ariana __ Japan T~ench__~ GApGE S:l::~E Rf'CO~IDED I .Tofino

HOUR HRS FROM EST,A~~ I~IT.WAVE MAX. WAVE YEAR HO. DAY (U.T.) LAT. LONG. }tAG~ DEPTH. GAUGE (U.!.) ARR. HI. ARR. HT. PERIOD CONMENTS .. 1896 June 15 1033 39.6N" 144.2E 7.6 1931 Mar 9 0349 4l.2N 142.5E7.6 . 10 1400 No tsunami 1933 }far 2 1731 39.1N l lf4.7E 8.3 9. 1/2 3/0300 . 0312 .10R 0457 23F 1936 Nov 2 2046 38.2N 142.2E 7.7 80 10 3/0700 No tsunami 1938 .. Nov 5 0843 36.7N ·141. 7E 7.1 33 10·i/2 1900 No tsunami 1938 Nov 5 . 1050 38.2N 141.7E 7.6 100 10 1/2 2130 No tsunami 1938 Nov 6 0854 36.9N 142~ 6E 7.5 '10 1/2 1930 , - No tsunami 1952 Mar 4 0123 42.2N . 143. 8E 8.1 45 10 1123 1150 3R 2112 12F 1953 Nov 25 1748 34N . 14l.5E 8.0. 50 10 '1/2 26/0430 .. No records 1960 Mar 20 1707 39.8N ·143.5E 7.5 .60 .10 . 21/0300 No tsunami 1964 . June 16 0402 38.3N 139.2E 7.5 . 57 - . Sea of Japan 1968 May 16 . 0049 40.9N 143.5E 8.2 7 9 1/2 1000 .. 1017 .5R 1625 12F , 1968 May 16 1039 . 41. 6N 142.9E 7.5 33 9 1/2 2000 Not identifiable over previous tsunami. TRAVEL TIMES OF MAJOR TSUNAMIS ~ . AREA OF ORIGIN: Ryukyu - Philippine Trench" GAUGE SITE RECORDED: " , Tofino HOUR HRS FROM EST.ARi INIT.WAVE MAX. WAVE 'I YEAR NO. DAY (U.T.) LAT. LONG. MAG. DEPTH GAUGE (U. T.) ARR. HT. ARR. HT." PERIOD COMMENTS

1911 June ,15 1426 29N 129E 8.7 12 1/2 16/0300 1921 Nov 11 1836 8N- 127E 7.5 14 12/0900 No tsunami 1923 'Sept 1 0259 35.2N 139.5E 8.2 11 1/2 1430 No tsunami 1923 Sept 2 0247 35N 137.5E 7.7 11 1/2 1415 No tsunami 1924 Apr 14 1620 6.5N 126.5E 8.3 15 15/0720 No tsunami 1944 Dec 7 0435 33.7N 136E 8.0 ' 11 1/2 1600 No record 1946 Dec 20 1919 33.0N 135!6E 8.1 11 1/2 21/0700 No tsunami 0 1952 Mar 19 1057 9.5N 126.7E 7.7 14 20/0100 No tsunami 1966 Mar 12 1631 24.2N 122.6E' '7.5 48 14 13/0631 No record 1968, Apr 1 0042 32.6N 132.2E 7~7 33 12 1242 No record 1968 Aug 1 2019 16.5N 122.2E 7.7 37 15 2/1100 No tsunami 1972 Jan 25 ' 0206 22.5N 122E 7.7 33 14 1600 No tsunami 1972 Dec 2 0020 6.5N 126.6E 7.7 33 15 1/2 1600, No tsunami

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AREA OF ORIGIN: S, China - Sulu - Celebe~ Seas' GAUGE SITE RECC)RPED: . __T",-,Q"-"f...,.i,,",,,n=o~_~_~ _

HOUR IlRS Fiimx EST .AR. IN1T. WAVE . MAX. WAVE YEAR HO. DAY (U.T•) -LAT. tONG. MAG. DEPTH GAUGE (U. T.) ARR. HT. ARR. HT. PERIOD COMMENTS 1897 Sept 20 1906 6N 122E .8.6 17 1918 Aug 15 . 1218 5.5N 123E 8.2 . 16 1/2 16/0500 " No tsunami 1934 Feb 14 0400, 1.7.5N . 119E 7.6 .15 1900 No tsunami 1937 Aug 20 1159 14,5N ' 121.5E 7 ~5. 15 1/2 21/0300 No tsunami 1948 Jan 24 1747 10.5N 122£- 8,2 15 '1/2 25/0900 No record 1976 Aug 16 1610 7.2N 123,7E 7.8 33 15 1/2 17/0800 No record

."",",.=o_=,!=,,~..•..•••.•.., ·1' h: ! i~ TRAVEL T:hms' OF MAJOR TS1JNAMIS

AREA OF ORIGIN: Java Trench - Banda Sea GAUGE SITE R~CO~)EO; Totino HOUR ERS FRO~ ~S+~~~. !NIT.WAVE MAX. WAVE YEAR MO. DAY (U.T.) LAT. LONG. MAG. DEPTH GAUGE Jd. T,;) ARlt. HT. MR. HT. PERIOD. COMHENTS

1883 Aug 27 0259 16.7S ·105.4E i7.1/2 Krakatoa Explosion 1938 May 19 1708 IS 120E 7.6. 16 20/0900 No tsunami 1939. Dec 21 '2100 ON 123E 8.0 100'. 16 22/1300 No tsunami 1965 Jan 24 0011 2.4S. 126.0E 7.6 . 6 15 1500 No record 1968 Aug 10 0207 1.4N 126.2E 7.8 33 15 1700 No tsunami TRAVEL TIMES OF MAJOR TSUNAMIS

AREA OF ORIGIN: N. New Guinea-Bismark ArchipeiagodAUGE SITE: RlI:CO~Dl~D: _T...:;o...:;f;.;;:i;.;;:n,..:..o ------

HOUR HRS FROM EST.AR, INIT,WAVE MAX. WAVE YEAR MO. DAY (U.T.) LAT. LONG. MAG. DEPTH GAUGE (U ~ T.) ARR. HT, ARR. HT. PERIOD COJ:.fMENTS 1914 May . 26 1423 28 137E 7.9 15 1/2 1935 Sept 20 0147 3.5S 141.8E 7~9 33 . 15 1700 No tsunami

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__.. ~._._.~.. ._ ..._, w._..·_.__ ._._·__··_··_ ..__·_.. J";1~:c;rio\~~ ._------_._--- TRAVEL TIMES OF MAJOR TSDNA}fIS

AAEA OF ORIGINi Solomon Sea - New Hebrides ' GAUGB S11'~ RECORDED! Tofino HOUR HRS }~OM Est.AR~ INrT.WAVE MAX.WAVE , YEAR MO. DAY (D.T.) LAT. LONG. MAG. DEPTH GAUGE l.U.T.) ARR. HT. ARR. HT. PERIOD' COMMENTS - e d 1919 May 6 1941 :is 154E 8.1 1l~ 1/2 7/0600 ' No record 1920 Feb 2 1122 6.58 150E ,,' 7.8 15 1/2 3/0300 ,No tsunami 1931 Oct' 3 1913 10.5S 16L8E 7.9 14 1/2 4/1000 0952 ,2R 1313' 6F 1934, July 18 1940 138 '166.5E 8.2 13 1/2 19/0900 No tsunami 1939 Jan 30 0218 6.5S 155.5E 7.8 33 14 1/2 1700 -- No tsunami 1939 Apr 30 0256 9.05 159.5E. 8~0 rso. 14 1/2 '1700 No tsunami 1949 Oct 19 2100 6.58 154E. 7.5 ' 60 14 1/2 20/1100 No tsunami 1953 Apr 23 1624 45 154E 7.5 14,1/2 24/0700 No record 1966 Jun~ 15 0132 10.38 160. SE, 7.6 ' 23, 14 1/2 1600, No record 1966 pee 31 1823 11.88 16?5E '7.7 56 14 1/0800 No record , 19i1 July 14 0611 5.58 153.9E 7.9 4i ' 1,5 2106 No record 1971 July 26 0123 4,98 ,153.2E 8.4 48 15 1600 No record , , 1975 July 20 1437 6.5S 154.9E 7.7 49 14 1/2 21/0500 'No tsunami

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• ••.. _._-, •.-._._-_... __"'lfI"" ..,,~.,.---. .: TRAVEL TIMES OF MAJOR TSUNAMIS

AREA OF ORIGIN: ~T~a~s~m~a~n~S~e~a~ ~ ~AUG~ si~:~ ~~c6¥Pf~; -=-T:.::;o..:::.f=in=,o~ _

HOUR HRS FRO}! ~S1'.M, INIT,WAVE MAX.WAVE YEAR MO. DAY CU. T ~ ) LAT. LONG. HAG. im:p±H GAUGE. CO. T.) . ARR. liT. ARR. liT. PERIOD COMMENTS

1924 June 26 0138 568 157E 7.8 . 19 .2100 No tsunami 1929 June 16 2248 41. 8S 172.2E 7.6 16 1/2 17/1500 . No tsunami

,. <-.~ ,.... ~'~.,.:::;: .. ~:::::-.::.;~_.~'.6,,;;I,'!""'~ ...i:-~,'1

...... ------_._ -._._-_._-_ __._- --'-'---'---.-._.. TRAVEL TIMES OF MAJOR TSUNAMIS

AREA OF ORIGIN: Kermadec - Tonga Trench GAUGE SITE RECORbp:p: _.T....:;.o....:;.f.::,in:.:.o::..-- _

'. TRAVEL TIMES OF MAJOR TSUNAMIS AREA OF ORIGIN: --=H.:::.aw~a::.:i==i=-- _ GAUGE SIT~ RECORDED: -=-===;;:.;:....------Tofino

HOUR nRS FROM Est.AR, INIT.WAvE MAX.WAVE I YEAR MO. DAY (U.T.) LAT. LONG. MAG. DEPTH GAUGE CU. T.) AllR. HT. ARR. HT. PERIOD COMMENTS

1975 Nov 29 1448 19. 4N 155.1W. 7.2.. 5 1/2 2018. ·2056 3R' 22029F

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