DEPARTMENT OF THE INTERIOR U.S. GEOLOGICAL SURVEY United States Earthquakes, 1973 By Jerry L. Coffman and Carl A. von Hake NOAA, Environmental Data Service and William Spence, David L. Carver, Pamela A. Covington, Gerald J. Dunphy, W. LeRoy Irby, Waverly J. Person, and Carl W. Stover, U.S. Geological Survey Open-File report 84-973 Prepared in cooperation with National Oceanic and Atmospheric Administration This report has not been reviewed for conformity with U.S. Geological Survey editorial standards. 1984 Preface In 1973, most seismological activities of the National Oceanic and Atmos­ pheric Administration (NOAA) were absorbed by the U.S. Geological Survey (USGS). These operations included the Seismological Research Group, National Earthquake Information Center, and Geomagnetic Research Group, Boulder, Colo.; Seismological Field Survey, San Francisco, Calif.; and Special Projects Party, Las Vegas, Nev. Although the seismology functions of the NOAA/Environ- mental Data Service remained intact, it was decided that the 1973 and subsequent issues of United States Earthquakes would be published jointly by NOAA/USGS. Except for minor changes, the format for this first joint report is essentially the same as that in past issues of United States Earthquakes. Ill Contents PAGE Introduction ................................................. 1 National Geophysical and Solar-Terrestrial Data Center .................. 1 National Earthquake Information Service ................................ 2 Seismology Collaborators ............................................... 4 Epicenter Maps ....................................................... 4 Magnitude and Intensity Ratings ....................................... 7 Modified Mercalli Intensity Scale of 1931 ................................ 7 Earthquake Descriptions ...................................... 11 Introduction .......................................................... 11 Summary of Earthquake Activity ....................................... 11 Northeastern Region .................................................. 12 Eastern Region ....................................................... 17 Central Region ....................................................... 24 Western Mountain Region ............................................ 25 California and Western Nevada ........................................ 26 Washington and Oregon ............................................... 40 Alaska ................................................................ 40 Hawaii ................................................................ 44 Panama Canal Zone ................................................... 52 Puerto Rico .......................................................... 52 Virgin Islands ......................................................... 52 Principal Earthquakes of the World .................................... 52 Miscellaneous Activities ....................................... 71 Horizontal Control Surveys for Crustal Movement Studies .................. 71 Vertical Movement Studies .............................................. 71 Tsunamis ............................................................. 71 Fluctuations in Well-Water Levels ....................................... 72 Strong-Motion Seismograph Data .............................. 79 Introduction .......................................................... 79 Accelerograph Records ................................................. 79 Additions and Corrections to Previous Issues .................... 87 Index of Town Names ........................................ 89 LIST OF TABLES TABLE PAGE 1 Instrumentally determined locations of earthquakes and related phe­ nomena that occurred in the United States during 1973 ............ 53 2 Principal earthquakes of the world during 1973 ...................... 68 3 Earthquake fluctuations in well-water levels during 1973 .............. 73 4 Earthquakes of 1973 believed to have caused fluctuations in well-water levels ......................................................... 77 5 Summary of accelerograph records obtained from earthquakes in 1973 ... 81 LIST OF ILLUSTRATIONS FIGURE PAGE 1 USGS and NOAA seismograph stations that routinely report basic seismological data to NEIS ...................................... 3 2 Damaging earthquakes in the United States from earliest history through 1973 .................................................. 5 3 Locations of earthquakes that were felt or caused damage in the United States during 1973 ............................................. 9 4 Area affected by western Maine earthquake of June 14 ............... 13 5 Area affected by New Jersey earthquake of February 28 ............... 18 6 Area affected by Florida earthquake of October 27 ................... 20 7 Area affected by eastern Tennessee earthquake of November 30 ........ 22 8 Chimney damage caused by eastern Tennessee earthquake of No­ vember 30 ..................................................... 23 9 November 30 earthquake cracked concrete porch in Maryville, Tenn. ... 23 10 USGS team sets up aftershock equipment in Maryville-Alcoa, Tenn., area following November 30 earthquake .......................... 23 11 Area affected by Point Mugu, Calif., earthquake of February 21 ........ 28 12 Landslide in Point Mugu, Calif., area resulting from February 21 tremor ........................................................ 29 13 Underwater craters in Point Mugu, Calif., submarine canyon, possibly caused by February 21 earthquake ............................... 30 14 Area affected by Hilo, Hawaii, earthquake of April 26 ................ 45 15 April 26 earthquake collapsed house foundation in area of Amauulo, Hawaii ........................................................ 46 16 Highway shoulder failure at Wainaku, Hawaii, caused by April 26 tremor ........................................................ 47 17 April 26 earthquake inflicted severe interior damage to Typewriter Center, downtown Hilo, Hawaii ................................. 48 18 Collapse of cesspool at Puueo, Hawaii, was attributed to April 26 tremor ........................................................ 49 19 Strong-motion stations in Cooperative National Network (excluding California) .................................................... 78 vi Introduction United States Earthquakes, prepared annually responsible for data activities in the field of since 1928, describes all earthquakes that were felt seismology. in the United States and nearby territories during Its services include preparing local and regional the year. Earthquakes are listed chronologically in seismic histories for engineers, actuaries, and other 11 regions: Northeastern Region, Eastern Region, scientists, and answering direct inquiries from the Central Region, Western Mountain Region, Cali­ public on all aspects of historical earthquakes. fornia and Western Nevada, Washington and Additional services and products include publishing Oregon, Alaska, Hawaii, Panama Canal Zone, annual earthquake summaries and revised his­ Puerto Rico, and Virgin Islands. In addition, table torical earthquake reports; and making available 1 contains instrumental epicenters of U.S. earth­ in several formats (at a nominal fee) copies of quakes and lists those that were not felt by resi­ seismograms, accelerograms, displacement meter dents; table 2 lists principal earthquakes of the records, digiti/ed strong-motion seismograms, and world for the year with brief accounts of their epicenter lists. Many of these products and services effects. are based on seismic records or other data that This report also includes sections on horizontal have originated with USGS recording networks or and vertical control surveys for crustal movement with USGS data-reduction facilities. Information studies, tsunamis, well-water fluctuations, and concerning services and products of NGSDC may strong-motion seismograph data. be obtained from the National Geophysical and Sources of noninstrumental information used in Solar-Terrestrial Data Center, NOAA/EDS, Boul­ this compilation include reports received from der, Colo. 80302. Some of these seismological questionnaire canvasses conducted by the U.S. services and products are described in the following Geological Survey National Earthquake Informa­ paragraphs. tion Service (NEIS) ; reports from seismology Earthquake Data File collaborators; newspaper clippings; bulletins of the The earthquake hypocenter data file lists hypo- Seismological Society of America; special reports of centers geographically and chronologically from other organizations; and felt data from NOAA's 1900-1974. It is available on magnetic tape and National Weather Service. 16-mm microfilm. Monthly updates on punched Instrumental data utilized in computing earth­ cards also may be purchased. The file gives date, quake epicenters, depths, magnitudes, and times of origin time, geographic location, focal depth, magni­ occurrence are obtained by NEIS from NOAA, tude, and intensity (Modified Mercalli) for each USGS, and cooperating seismological observatories, event when available. Searches for one, or combina­ both domestic and foreign. tion, of the parameters above can be made. Addi­ tional information is available on request. Strong-Motion Earthquake Data NATIONAL GEOPHYSICAL All records in the strong-motion file, dating from AND SOLAR-TERRESTRIAL the initial accelerograms recorded in 1933, are DATA CENTER available in full-size paper copies or as 70-mm film chips. A chronological listing