Earthquakes in the United States, January March 1975 Earthquakes in the United States, January March 1975
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GEOLOGICAL SURVEY CIRCULAR 749-A Earthquakes in the United States, January March 1975 Earthquakes in the United States, January March 1975 By R. B. Simon, C. W. Stover, and W. J. Person GEOLOGICAL SURVEY CIRCULAR 749-A 1977 United States Department of the Interior CECIL D. ANDRUS, Secretary Geological Survey V. E. McKelvey, Director Free on application to Branch of Distribution, U.S. Geological Survey, 1200 South Bads Street, Arlington, VA 22202 CONTENTS Page Introduction................................................. 1 Discussion of tables............................................................ 1 Modified tlercalli Intensity Scale of 1931....................................... 5 Acknowledgments................................................................. 34 References cited................................................................ 35 ILLUSTRATIONS Page FIGURE 1. "Earthquake Report" form.............................................. 2 2. Hap showing standard time zones of the conterminous United States..... 4 3. Map showing standard time zones of Alaska and Hawaii.................. 5 4. Map of earthquake epicenters in the conterminous United States for January-March 1975.................................................... 6 5. Map of earthquake epicenters in Alaska for January-March 1975......... 7 6. Map of earthquake epicenters in Hawaii for January-March 1975......... 9 7. Isoseismals for the central California earthquake of 6 January 1975... 19 8. Isoseismals for the northern California earthquake of 12 January 1975.................................................................. 20 9. Intensity map for the southern California earthquake of 13 January 1975.................................................................. 21 10. Isoseismals for the southern California earthquake of 23 January 1975.................................................................. 23 11. Isoseismals for the Idaho-Utah border region earthquake of 28 March 1975.................................................................. 28 12. Photograph of damaged metal siLo on Fuhriman's farm in Pocatello Valley, Idaho......................................................... 29 13. Isoseismals for the northwestern Montana earthquake of 4 February 1975.................................................................. 33 TABLES Page TABLE 1. Summary of U.S. earthquakes for January-March 1975: Alabama.......................................................... 1° Alaska........................................................... 10 Arkansas......................................................... 12 California....................................................... 12 California Off the coast........................................ 13 Colorado......................................................... 13 Hawaii........................................................... 13 Idaho............................................................ 15 Illinois......................................................... 15 Missouri......................................................... 15 Montana.......................................................... 15 Nevada........................................................... 15 New Mexico....................................................... 15 New York......................................................... 15 Ohio............................................................. 15 Oregon Off the coast............................................ 15 III Page TABLE 1. Summary of U.S. earthquakes for January-March 1975: Utah............................................................. 15 Virginia......................................................... 16 Washington....................................................... 16 Washington Off the coast........................................ 16 Wyoming.......................................................... 16 2. Summary of raacroseismic data for U.S. earthquakes, January-March 1975: Alabama.......................................................... 16 Alaska........................................................... 15 Arkansas......................................................... 19 California....................................................... 19 California Off the coast........................................ 24 Colorado......................................................... 25 Hawaii........................................................... 25 Idaho............................................................ 27 Illinois......................................................... 32 Missouri......................................................... 32 Montana.......................................................... 32 Nevada........................................................... 33 New Mexico....................................................... 33 New York......................................................... 34 Ohio............................................................. 34 Virginia......................................................... 34 Washington...................................................... 34 Wyoming.......................................................... 34 IV Earthquakes in the United States, January-March 1975 By R. B. Simon, C. W. Stover, and W. J. Person INTRODUCTION Box 25046, Denver Federal Center, Denver, Colo. 80225. Copies of the "Earthquake Report" The earthquake information in this questionnaire can be obtained at this address. publication supplements that published in the NEIS The primary method used by the NEIS to (National Earthquake Information Service) collect macroseismic information is a publications, PDE ("Preliminary Determination of questionnaire canvass using the "Earthquake Epicenters") and "Preliminary Determination of Report" forms, which are mailed to postmasters in Epicenters, Monthly Listing," to the extent of the area affected by the earthquake. The providing detailed felt and intensity data, as postmasters complete the forms and return them to well as isoseismal maps for U.S. earthquakes. the NEIS, where they are evaluated and an The purpose is to provide a complete listing of intensity value assigned. The intensity macroseismic effects of earthquakes, which can be observations are mapped and contoured by used in risk studies, nuclear power plant site isoseismals. Isoseismal contours present a evaluations, seismicity studies, and answering generalization of intensity data and an inquiries by the public. extrapolation of these data to regions from which This publication contains two major sections. there are no observations; they do not The first (table 1) is a tabular listing of necessarily account for every individual earthquakes in chronological order by State, consisting of the following basic information: observation. date, origin time, hypocenter, magnitude, maximum The data in table 2 will be included in the intensity, and the computational source of the "Earthquake Description" section of "United States hypocenter. The second section consists of 11 Earthquakes," an annual publication, to which maps, one photograph, and table 2, which lists later data from other sources may be added for the detailed intensity information. The list of purpose of updating and completeness. "United earthquakes in table 1 was compiled from those States Earthquakes" is published jointly by the located in the United States or off the coasts U.S. Geological Survey, Department of the that were published in the PDE; from hypocenters Interior, and the Environmental Data Service, in California above magnitude 3.0, supplied by NOAA, Department of Commerce. California Institute of Technology, Pasadena, and the University of California, Berkeley; from DISCUSSION OF TABLES hypocenters in Hawaii supplied by the Hawaiian The parameters for the earthquakes in table 1 Volcano Observatory; and from any others that and table 2 include the date, origin time, were felt or that caused damage, regardless of hypocenter (epicenter and focal depth), magnitude, magnitude or availability of a hypocenter. Known intensity, and hypocenter source. The origin time or suspected explosions are also listed. and date are listed in Universal Coordinated Time The intensities and macroseismic data were (UTC) and local standard time based on the compiled from information obtained through time-zone maps in figures 2 and 3. The questionnaires (fig. 1), from newspaper articles, epicenters, which were taken from those published and with the cooperation of other government in the PDE, or from other sources as noted, are agencies, State institutions, local organizations, listed here to two decimals. The accuracy of the and individuals. (See "Acknowledgments" for a epicenters is that claimed by the institution list of collaborators.) Anyone wishing to submit supplying the hypocenter and is not necessarily felt or damage information on earthquakes for the accuracy indicated by the number of decimals inclusion in future reports should send it to the listed. The epicenters located by the NEIS have a National Earthquake Information Service, Stop 967, varying degree of accuracy, usually two-tenths of U.S. DEPARTMENT OF THE INTERIOR Form Approved GEOLOGICAL SURVEY OMB No. 42-R1700 EARTHQUAKE REPORT Please answer t«iis questionnaire carefully and return as soon as possible. 1. Was an earthquake felt by anyone in your town or zip code area recently? D Not felt: Please refold and tape for return mail. D Felt: Date__________Time_______ DAM D Standard time D PM