Earthquakes in the United States, October-December 197 4
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GEOLOGICAL SURVEY CIRCULAR 723-D Earthquakes in the United States, October-December 1974 Earthquakes in the United States, October-December 1974 By C. W. Stover, R. B. Simon, and W. J. Person G E 0 L 0 G I C A L 5 U R V E Y C I R C U L A R 7 2 3-D 1976 United States Department of the Interior THOMAS S. KLEPPE, Secretary Geological Survey V. E. McKelvey, Director Free on application to the Branch of Distribution, Eastern Region, U.S. Geological Survey, 604 South Pickett Street, Alexandria, VA 22304 CONTENTS Page Introduction . D1 Discussion of tables . 3 Modified Mercalli Intensity Scale of 1931 . 12 Acknowledgments . 26 References cited . 27 ILLUSTRATIONS Page F!GlTHE 1. "Earthquake Report" form . D2 2. Map showing standard time zones of the conterminous United States . 3 3. Map showing standard time zones of Alaska and Hawaii . 4 4. Map of earthquake epicenters in the conterminous United States for October- December 1974 . 5 5. Map of earthquake epicenters in Alaska for October-December 1974 . 6 6. Map of earthquake epicenters in Hawaii for October-December 1974 . 12 7. Map summarizing the earthquake epicenters in the conterminous United States for January-December 1974 . 13 8. Map summarizing the earthquake epicenters in Alaska for January-December 1974 . 14 9. Map summarizing the earthquake epicenters in Hawaii for ,January-December 1974 . 15 10. Isoseismals for the central California earthquake of 28 November 1974 . 18 11. Isoseismals for the eastern South Carolina earthquake of 22 November 1974 . 23 TABLES TAHLE 1. Summary of United States earthquakes for October-December 1974: Page Alabama ............................................................. D7 Alaska ............................................................... 7 Arizona .............................................................. 9 Arkansas ............................................................. 9 California ............................................................ 9 California-Off the coast .............................................. 10 IIawaii .............................................................. 10 Idaho ................................................................ 10 Missouri ............................................................. 11 Montana ............................................................. 11 New Mexico .......................................................... 11 Oklahoma ............................................................ 11 Oregon .............................................................. 11 Oregon-Off the coast ................................................. 11 Rhode Island ......................................................... 11 South Carolina ....................................................... 11 III Page TABLE 1. Summary of United States earthquakes for October-December 1974-Continued Texas................................................................. D11 Utah . 11 Washington . 11 West Virginia . 12 Wyoming . 12 2. Summary of macroseismic data for United States earthquakes, October- December 1974: Alabama.............................................................. 15 Alaska................................................................ 15 Arizona . 16 Arkansas . 16 California . 16 California-Off the coast . 19 Hawaii . 19 Idaho................................................................. 22 Oklahoma . 22 Oregon . 22 Rhode Island . 22 South Carolina . 22 Utah . 23 Washington . 23 West Virginia . 23 Wyoming ................................ __ . 24 IV Earthquakes in the United States, October-December 197 4 By C. W. Stover, R. B. Simon, and W. J. Person INTRODUCTION the cooperation of other government ap-encies, State institutions, local organizations, Fnd in The earthquake information in this publication dividuals. (See "Acknowledgments" for a list of supplements that contained in the NElS (National collaborators.) Anyone wishing to submit felt or Earthquake Information Service) publications, damage information on earthquakes for inclusion PDE ("Preliminary Determination of Epicenters") in future reports should send it to the National and "Preliminary Determination of Epicenters, Earthquake Information Service, Stop 9f7, Box Monthly Listing," to the extent of providing 25046, Denver Federal Center, Denver, Colo. 80225. detailed felt and intensity data, as well as Copies of the "Earthquake Report" questirmnaire isoseismal maps for U.S. earthquakes. The purpose can be obtained at this address. is to provide a complete listing of macroseismic ef The primary method used by the NElS tC' collect fects of earthquakes, which can be used in risk macroseismic information was a questionnaire can studies, nuclear power plant site evaluations, vass using the "Earthquake Report" forms, which seismicity studies, and answering inquiries by the were mailed to postmasters in the area affe~ted by public. the earthquake. The postmasters comple~ed the This publication contains two major sections. forms and returned them to the NElS, where they The first (table 1) is a tabular listing of earth were evaluated and an intensity value was as quakes in chronological order by State, consisting signed. Using these values, isoseismal lin~s were of the following basic information: date, origin drawn on maps to separate regions characterized time, hypocenter, magnitude, maximum intensity, by a group of one or more ranges of intensity. Any and the computational source of the hypocenter. isoseismalline may include a lower or higher inten The second section consists of two maps and table sity if it falls among a set of the values being con 2, which lists detailed intensity information. The toured and cannot be differentiated exce}: t as an list of earthquakes in table 1 was compiled from isolated point. Anomalous intensities located some those located in the United States or off the coasts distances from the contiguous data may not be that were published in the PDE; from hypocenters enclosed within the isoseismal lines. These inten in California above magnitude 3.5, supplied by sities are not considered when calculating the felt California Institute of Technology, Pasadena, and area. the University of California at Berkeley; and from These data will be included in the "Earthquake any others that were felt or that caused damage, Description" section of "United States Earth regardless of magnitude or availability of a quakes," an annual publication, to which later hypocenter. Known or suspected explosions are data from other sources may be added for the pur also listed. poses of updating and completeness. "United The intensities and macroseismic data were States Earthquakes" is published jointly by the compiled from information obtained through U.S. Geological Survey, Department of the questionnaires (fig. 1) sent to post offices in the Interior, and the Environmental Data Service, epicentral area, from newspaper articles, and with NOAA, Department of Commerce. Dl U.S. DEPARTMENT OF THE INTERIOR Form Approved GEOLOGICAL SURVEY OMB No. 41--R0013 EARTHQUAKE REPORT An earthquake was felt D notfelt 0 Time ------A.M. Date of shock ------------------- ------- P.M. If felt, please supply information below (Underline appropriate words or fill spaces.) If not felt, please s1gn and return card, wh1ch requ1res no postage. a. City. County, State ..., Township, Range, Section, Quarter Section. or Geographic Coordinates -=c b. Ground: !:) Rocky, gravelly, loose, compact, marshy, ~illed in, or o:cz:O'_...., .... a.: Level, sloping, steep, or u...,cc 9c:» c. H inside, type of construction: d. Quality of construction: ac:~ ::;,ac: Wood, bnck, stone, or New. old, well bu1lt. poorly bu11t, or o=>o-Q e. No. of floors I. Observer's g. Activity when earthquake occurred: h. H outside, you, N in buildin1: floor: Walkmg, s1tting, lymg down, others were: sleepmg Qu1et, active a. Felt by: !~ No one, very few, several, many, all (10 your home) (in community) ~= b. Awakened: fdS No one, few, many, all (in your home) (in community) ~A. ~0 c. Friahtened: ...,A. cw; No one, few, many, all (in your home) (m community); general panic Ccn a. Raltlinl of windows, doors, dis._, etc . ...,Q.... z :5=...,0 b. Creakin1 of buildinl (Describe) a.:: en • c. Earth noises: Faint, moderate, loud a. Outside: ..., (1) Trees and bushes shaken, vehicles rocked, etc . ~ (2) Ground cracked; landslides; water disturbed, etc :. c (3) Ch1mneys, tombstones, elevated water tanks, etc., cracked, twisted, Q Q overturned cz (4) Other effects ~ b. Buildinp: fd (1) Hanging objects swung moderately, VIolently Direction ~ ...,~ (2) Small objects shifted, overturned, fell ..... c (3) Furniture shifted, overturned, broken u (4) Plaster cracked, broken, fell :cie (5) Windows cracked A. .,.; (6) Structural elements of brick, wood, or Damage: None, slight, moderate, great S1gnature and address of observer Additional inform.UO. would be appreciated. Use spiCe on reverse side. FIGtrRE 1.-Example of the "Earthquake Report" form used for evaluating the intensities of earthquakes. D2 DISCUSSION OF TABLES quake activity for the conterminous Unite1 States, Alaska and Hawaii for the periods Oc The parameters for the earthquakes in table 1 1974. The annual summaries are and table 2 include the date, origin time, tober-D~cember shown in figures 7-9. The magnitudes plotted in hypocenter (epicenter and focal depth), these figures are based on M Lor m bLg' if neither magnitude, intensity, and hypocenter source. The was computed, then on M , and finally on mb, origin time