DOCSLIB.ORG

United States Earthquakes, 1971 Open-File Report 84-971 Prepared

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
United States Earthquakes, 1971 Open-File Report 84-971 Prepared DEPARTMENT OF THE INTERIOR U.S. GEOLOGICAL SURVEY United States Earthquakes, 1971 By Jerry L. Coffman and Carl A. von Hake Open-File report 84-971 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 The Environmental Data Service does not approve, recommend, or endorse any proprietary product or proprietary material mentioned in this publication. No reference shall be made to the Environmental Data Service, or to this publication furnished by the Environmental Data Service, in any advertising or sales promotion which would indicate or imply that the Environmental Data Service approves, recommends, or endorses any proprietary product or proprietary material mentioned herein, or which has as its purpose an intent to cause directly or indirectly the ad­ vertised product to be used or purchased because of this Environmental Data Service publication. Contents LIST OF TABLES Page Table \ Instrumentally determined locations of earthquakes and related phenomena that occurred in the United States during 1971 ........................ 79 2 Principal earthquakes of the world during 1971 ........................ 97 3 Fluctuations in well-water levels during 1971 ........................... 104 4 Earthquakes in 1971 believed to have caused fluctuations in well-water levels. 110 5 Occurrence of 'earthquakes and number of records for 1971 ............ 119 6 Compilation of strong-motion accelerograph data for 1971 .............. 120 7 Compilation of southern California seismoscope stations and data for the San Fernando earthquake of February 9. 1971 ............................. 170 LIST OF ILLUSTRATIONS Page 1 I Xunagiiiu earthquakes in (lie United Stales from earliest history through 1971. 5 2 Locations of earthquakes thai were felt or caused damage in the United States during 1971 ........................................................ 10 3 Area affected by Arkansas earthquake of October 1 .................... 15 4 Area affected by San Fernando, Calif., earthquake of February 9 ........ 23 5 Kpiccntral area of San Fernando. Calif., earthquake of February 9 ....... 26 6 Area affected by southern California earthquake of March 31 ........... 62 7 XOAA strong-motion accelerograph network (as of June 30. 1972) ...... 112 8 Act elerograph slalions in central and southern California during San Fernando earthquake ......................................................... 114 9 At c clerograph slalions in extended Los Angeles area during San Fernando earthquake ......................................................... 115 10 Accelerograph slalions in central Los Angeles during San Fernando earthquake ......................................................... 116 1 1 Seisnmscope location map for southern California network during San Fernando earthquake ................................................ 117 12 Magnitude and direction of maximum seismoscope response of each station during San Fernando earthquake ..................................... 118 Introduction United States Earthquakes, prepared an­ for data activities in the field of seismology. nually since 1928, lists epicenters of all earth­ NGSDC is a focal point for the dissemina­ quakes and associated phenomena recorded tion of historical seismic information for both in the United States and nearby territories technical and general users. Its services in­ during the year. It includes brief descriptions clude preparing local and regional seismic of earthquakes that were felt or caused histories for engineers, actuaries, and other damage in the United States, and summarizes scientists; answering direct inquiries from the all available data on tremors noted by public on all aspects of historical earth­ residents of the Panama Canal Zone, Puerto quakes; publishing annual, quarterly, month­ Rico, and the Virgin Islands. In addition, a ly, and revised historical earthquake reports; list of principal earthquakes of the world and making available at a nominal fee copies during the year is presented with brief ac­ of seismograms, accelerograms, displacement counts of their effects. meter records, digitized strong-motion Sources of noninstrumental information seismograms, and epicenter lists (since used in this compilation include reports January 1900). Information concerning ser­ received from questionnaire canvasses, vices and products of NGSDC may be ob­ newspaper clippings, bulletins of the tained from the National Geophysical and Seismological Society of America, special Solar-Terrestrial Data Center, Environmental reports of other organizations, and data from Data Service, National Oceanic and At­ the National Weather Service of NOAA mospheric Administration, Boulder, Colorado whose observers prepare periodic reports on 80302. Some of the seismological services and local seismic activity. products are described in the following Instrumental data utilized in computing paragraphs. earthquake locations, depths, magnitude, and times of occurrence are obtained from Earthquake Epicenter Data NOAA and cooperating seismological ob­ The earthquake data files contain data on servatories, both domestic and foreign. earthquakes, known or suspected explosions, associated collapse phenomena, coal bumps, rock bursts, quarry blasts, and other earth NATIONAL GEOPHYSICAL disturbances recorded by seismographs. The AND SOLAR-TERRESTRIAL date, origin time, geographic location, focal DATA CENTER depth, magnitude, and Modified Mercalli in­ tensity are listed for each event when The National Geophysical and Solar- available. These data may be obtained on Terrestrial Data Center (NGSDC), previously magnetic tape, punched cards, or microfilm. the National Geophysical Data Center and the Aeronomy and Space Data Center, is one Conventional Seismograms of the five major facilities of NOAA's En­ Copies of seismograms from the World­ vironmental Data Service. NGSDC's Solid wide Network of Standard Seismographs Earth Data Services Division is responsible (WWNSS) and other selected foreign 1 United States Earthquakes, 1971 stations, as well as from the Canadian and Institute of Technology, Pasadena. The 114 NOAA networks of seismic stations, are records in the six series represent the record­ available in 35-mm. or 70-mm. film format or ed data for 22 earthquakes in California, as full-size paper copies. Montana, and Washington. High-Gain, Long-Period Seismograms Publications Seismograms from January 1971 recorded Publications issued by NGSDC include the at Albuquerque, N. Mex., Ogdensburg, N.Y., following: Fairbanks, Alaska, Eilat, Israel, and Charters 1. C&GS Special Publication 282, Earthquake Towers, Australia, are now available. Ad­ Investigation in the United States (Revised 1969 ditional stations have been installed recently Edition). This semitechnical booklet explains in Toledo, Spain, Chieng-Mai, Thailand, important facts about earthquakes and Honolulu, Hawaii, Matsushiro, Japan, and discusses major historical shocks of the Kongsberg, Norway. The records are on stan­ United States and nearby territories. It also dard-size paper, and reproductions can be contains sections on seismographs and the obtained in the same formats and costs as the nature of earthquakes and seismic waves. WWNSS seismograms. Six components are 2. C&GS Publication No. 41-1, Earthquake recorded daily three high- and three in­ History of the United States (Revised Edition termediate-gain values in the vertical, north- Through 1970). This report describes south, and east-west directions. prominent earthquakes (generally Modified Mercalli intensity V and above) in the United Earthquake Strong-Motion Data States from historical times through 1970. It All records from the NOAA strong-motion contains regional tables that list earthquake file, starting from the initial accelerograms epicenters or probable locations, intensity, and displacement meter records recorded in and extent of felt area. 1932, may be obtained in full-size paper The preceding reports were prepared in copies, film chips, or 35-mm. roll film. collaboration with Environmental Research A set of accelerograms from 227 locations Laboratories (ERL) groups, especially the affected by the San Fernando, Calif., earth­ Seismological Field Survey and the National quake in February 1971 is also available. Earthquake Information Center. Records are generally from Los Angeles and surrounding areas and include (among others) recordings from Pacoima Dam, San Onofre, EARTHQUAKE EARLY Vernon, and Santa Ana. REPORTING SYSTEM Additional conventional seismograms from the February 9, 1971, earthquake also can be The ERL National Earthquake Informa­ purchased on 70-mm. film, 35-mm. film, or tion Center (NEIC) maintains an earthquake as full-size paper copies. These include most reporting system that provides accurate and of the WWNSS seismograms, as well as rapid epicenter locations and magnitude records from many nonstandard stations. values to the press and other interested Digitized accelerograms of strong earth­ groups. These results are available within 2 to quake ground motions, as processed from 3 hours for earthquakes of magnitude 6'/z or records of the Environmental Research larger. Locations and magnitudes of smaller Laboratories (previously Coast and Geodetic events are computed on request or on receipt Survey records) accelerograph network, are of a press report. NEIC relies on NOAA and available on magnetic tape or punched cards. cooperating observatories
Load more

Recommended publications
  • Risk Assessment
    3 Risk Assessment Many kinds of natural and technological hazards impact the state of Alabama. To reduce the loss of life and property to the hazards that affect Alabama, state and local officials must have a robust and up-to-date understanding of the risks posed by these hazards. In addition, federal regulations and guidance require that certain components be included in the risk assessment section of state hazard mitigation plans (see Title 44 Code of Federal Regulations (CFR) Part 201 for federal regulations for mitigation planning and the State Mitigation Plan Review Guide for the Federal Emergency Management Agency’s (FEMA) official interpretation of these regulations). The required components are as follows: • An overview of the type and location of all natural hazards that can affect the state, including information on previous occurrences of hazard events and the probability of future hazard events. According to the State Mitigation Plan Review Guide, the probability of future hazard events “must include considerations of changing future conditions, including the effects of long-term changes in weather patterns and climate;” • An overview and analysis of the state’s vulnerability to these hazards. According to the CFR, the state risk assessment should address the jurisdictions most threatened by the identified hazards, as well as the state assets located in the identified hazard areas; • An overview and analysis of the potential losses to the identified vulnerable structures. According to the CFR, the state risk assessment should estimate the potential dollar losses to state assets and critical facilities located in the identified hazard areas. The Alabama State Hazard Mitigation Plan Update approved by FEMA in 2013 assessed statewide risks based on the best available data at the time and complied with existing federal regulations and policy.
    [Show full text]
  • Preliminary 2021 National Seismic Hazard Model for Hawaii
    Preliminary 2021 National Seismic Hazard Model for Hawaii M. Petersen, A. Shumway, P. Powers, M. Moschetti, A. Llenos, A. Michael, C. Mueller, D. McNamara, A. Frankel, P. Okubo, Y. Zeng, S. Rezaeian, K. Jaiswal, J. Altekruse, S. Ahdi, and K. Rukstales USGS Update of the Hawaii Seismic Hazard Model Workshop #2 Virtual Workshop (Microsoft Teams) – November 18, 2020 U.S. Department of the Interior These data are preliminary or provisional and are subject to revision. They are being provided to meet the need for U.S. Geological Survey timely best science. The data have not received final approval by the U.S. Geological Survey (USGS) and are provided Geologic Hazard Science Center (Golden, CO) on the condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the data ■ USGS https://earthquake.usgs.gov/hazards/ sciencefor a changingworld Microsoft Teams Control Bar • When not speaking, please mute your microphone (or please do not be offended if the moderator does it for you!) • When not speaking, please turn off your camera. This also helps save bandwidth, which can help with picture and audio quality issues. • If you have a question, please "raise your hand" or type your question or comment into the meeting chat. Click on the hand when you are done to "unraise your hand". ■ • Troubleshooting: Try leaving and re-entering the meeting. Share your screen Web App Desktop App 00 - co L.....J8 r;ni_,J ••• ■ ◄ ~I [_+Jt ,_ leave v See participants ~USGS USGS Update
    [Show full text]
  • Optimizing Multi-Station Template Matching to Identify and Characterize Induced Seismicity in and Around Ohio
    Optimizing Multi-Station Template Matching to Identify and Characterize Induced Seismicity in and Around Ohio Final Technical Report for USGS NEHRP Award No. G15AP00089 PI: Michael R. Brudzinskia 1 Co-PI: Brian S. Curriea 2 Grad Student Supported: Robert J. Skoumala 3 aDepartment of Geology and Environmental Earth Science, Miami University, Oxford, OH, [email protected], 001-513-529-3216 [email protected], 001-513-529-3216 [email protected], 001-515-401-8271 Project dates: June 1, 2015 to May 31, 2016. Key Results 1. Multistation template matching finds swarms that help discern induced seismicity 2. 2 swarms were correlated with wastewater disposal, 3 with hydraulic fracturing 3. 17 other cataloged earthquakes between 2010-2014 were non-swarmy, likely natural Abstract This study investigated the utility of multistation waveform cross correlation to help discern induced seismicity. Template matching was applied to all Ohio earthquakes cataloged since the arrival of nearby EarthScope TA stations in late 2010. Earthquakes that were within 5 km of fluid injection activities in regions that lacked previously documented seismicity were found to be swarmy. Moreover, the larger number of events produced by template matching for these swarmy sequences made it easier to establish more detailed temporal and spatial relationships between the seismicity and fluid injection activities, which is typically required for an earthquake to be considered induced. Study results detected three previously documented induced sequences (Youngstown, Poland Township, and Harrison County) and provided evidence that suggests two additional cases of induced seismicity (Belmont/Guernsey County and Washington County). Evidence for these cases suggested that unusual swarm-like behaviors in regions that lack previously documented seismicity can be used to help distinguish induced seismicity, complementing the traditional identification of an anthropogenic source spatially and temporally correlated with the seismicity.
    [Show full text]
  • Database of Potential Sources for Earthquakes Larger Than Magnitude 6 in Northern California
    U. S. DEPARTMENT OF THE INTERIOR U. S. GEOLOGICAL SURVEY DATABASE OF POTENTIAL SOURCES FOR EARTHQUAKES LARGER THAN MAGNITUDE 6 IN NORTHERN CALIFORNIA By The Working Group on Northern California Earthquake Potential Open-File Report 96-705 This report is preliminary and has not been reviewed for conformity with U.S. Geological Survey editorial standards or with the North American stratigraphic code. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. 1996 Working Group on Northern California Earthquake Potential William Bakun U.S. Geological Survey Edward Bortugno California Office of Emergency Services William Bryant California Division of Mines & Geology Gary Carver Humboldt State University Kevin Coppersmith Geomatrix N. T. Hall Geomatrix James Hengesh Dames & Moore Angela Jayko U.S. Geological Survey Keith Kelson William Lettis Associates Kenneth Lajoie U.S. Geological Survey William R. Lettis William Lettis Associates James Lienkaemper* U.S. Geological Survey Michael Lisowski Hawaiian Volcano Observatory Patricia McCrory U.S. Geological Survey Mark Murray Stanford University David Oppenheimer U.S. Geological Survey William D. Page Pacific Gas & Electric Co. Mark Petersen California Division of Mines & Geology Carol S. Prentice U.S. Geological Survey William Prescott U.S. Geological Survey Thomas Sawyer William Lettis Associates David P. Schwartz* U.S. Geological Survey Jeff Unruh William Lettis Associates Dave Wagner California Division of Mines & Geology
    [Show full text]
  • Building for the Earthquakes of Tomorrow Complying with Executive Order 12699 IS-8.A / February 2006
    \ Building for the Earthquakes of Tomorrow Complying with Executive Order 12699 IS-8.A / February 2006 Table of Contents Copyright Permissions ............................................................................................................... iii Background ................................................................................................................................... v Course Goals and Objectives.................................................................................................... vii Unit 1: Course Introduction ....................................................................................................... 1-1 Unit 2: Executive Order 12699 .................................................................................................. 2-1 Unit 3: Earthquake Causes and Characteristics ......................................................................... 3-1 Unit 4: Earthquake Effects ......................................................................................................... 4-1 Unit 5: Protecting Your Community.......................................................................................... 5-1 Unit 6: Evaluating Your Community’s Safety........................................................................... 6-1 Unit 7: Conclusions.................................................................................................................... 7-1 Appendix A: Major Earthquakes in the United States, Mexico, and Canada, 1700-2004 ....... A-1 Appendix B:
    [Show full text]
  • PEER 2014/17 OCTOBER 2014 Disclaimer
    PACIFIC EARTHQUAKE ENGINEERING RESEARCH CENTER PEER NGA-East Database Christine A. Goulet Tadahiro Kishida Pacific Earthquake Engineering Research Center Timothy D. Ancheta Risk Management Solutions, Newark, California Chris H. Cramer Center for Earthquake Research and Information University of Memphis Robert B. Darragh Walter J. Silva Pacific Engineering and Analysis, Inc. El Cerrito, California Youssef M. A. Hashash Joseph Harmon University of Illinois, Urbana-Champaign Jonathan P. Stewart University of California, Los Angeles Katie E. Wooddell Pacific Gas & Electric Company Robert R. Youngs AMEC Environment and Infrastructure Oakland, California PEER 2014/17 OCTOBER 2014 Disclaimer The opinions, findings, and conclusions or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the views of the study sponsor(s) or the Pacific Earthquake Engineering Research Center. PEER NGA-East Database Christine A. Goulet Tadahiro Kishida Pacific Earthquake Engineering Research Center Timothy D. Ancheta Risk Management Solutions, Newark, California Chris H. Cramer Center for Earthquake Research and Information University of Memphis Robert B. Darragh Walter J. Silva Pacific Engineering and Analysis, Inc. El Cerrito, California Youssef M. A. Hashash Joseph Harmon University of Illinois, Urbana-Champaign Jonathan P. Stewart University of California, Los Angeles Katie E. Wooddell Pacific Gas & Electric Company Robert R. Youngs AMEC Environment and Infrastructure Oakland, California PEER Report 2014/17 Pacific Earthquake Engineering Research Center Headquarters at the University of California, Berkeley October 2014 ii ABSTRACT This report serves as a documentation of the ground motion database development for the NGA- East Project. The ground motion database includes the two- and three-component ground-motion recordings from numerous selected events (M > 2.5, distances up to 1500 km) recorded in the Central and Eastern North America (CENA) region since 1988.
    [Show full text]
  • Earthquakes in Hawaii: What You Need to Know
    Earthquakes in Hawaii: What you need to know U.S. Department of the Interior Prepared by: Janet L. Babb U.S. Geological Survey Hawaiian Volcano Observatory The State of Hawaii experiences thousands of earthquakes every year. Most of these earthquakes are closely related to volcanic processes in Hawaii, and are so small they can be detected only by seismometers. 03-06 00:00 12:00 More than 500 earthquakes were recorded by a nearby seismometer during the Kamoamoa fissure eruption Hawaii Standard Time along Kīlauea’s East Rift Zone on March 6, 2011. 23:30 0 + Minutes 30 Many earthquakes are strong enough to be felt on one or more islands. Locations of the 481 magnitude-3.0 and stronger earthquakes that were recorded during 2005–2015. Color and size of dots reflect earthquake magnitude: 3 4 5 6 7 M a g n i t u d e Source: USGS Hawaiian Volcano Observatory Some earthquakes are large enough to cause damage and impact residents across the State of Hawaii. Since 1868, more than 30 magnitude-6.0 or greater earthquakes have rattled the islands. Source: USGS Fact Sheet 2011-3013 (http://pubs.usgs.gov/fs/2011/3013) Two ways to measure or describe earthquakes: Magnitude and Intensity Magnitude Measures the amount of seismic energy released during an earthquake. A unit increase in magnitude corresponds to a ~ 30-fold increase in released energy. Compared to a M-3.0 earthquake… • a M-4.0 earthquake releases ~ 30 times more energy! • a M-5.0 earthquake releases ~ 1,000 times more energy!! • a M-6.0 earthquake releases ~ 30,000 times more energy!!! • a M-7.0 earthquake releases ~ 1,000,000 times more energy!!!! Intensity Describes what people experience during an earthquake— the effects of shaking on structures and the extent of damage.
    [Show full text]
  • EERI / SEAOH / UH Compilation of Reports on the October 15, 2006
    Compilation of Observations of the October 15, 2006 Kiholo Bay (Mw 6. 7) and Mahukona (Mw 6.0) Earthquakes, Hawai‘i December 31, 2006 Kalahikiola Church in Hawi, North Kohala, Island of Hawai‘i Contributors Gary Chock (Contributor and Editor) Troy Kindred Ian Robertson Gen Iinuma Peter Nicholson Ernest Lau Horst Brandes Afaq Sarwar Edward Medley John Dal Pino Paul Okubo William Holmes Barry Hirshorn Structural Engineers Association of Hawaii Jiro Sumada Hawaii State Earthquake Advisory Committee Acknowledgements This report was compiled by EERI member Gary Chock of Martin & Chock, Inc., Honolulu, Hawai`i for the Earthquake Engineering Research Institute and the Structural Engineers Association of Hawaii as part of the initial reconnaissance after the earthquake. He drew on his own observations as well as information from, and materials prepared by a number of other professionals: Ian Robertson, Peter Nicholson, and Horst Brandes, of the University of Hawai`i at Manoa; Edward Medley, the Geo-Engineering Earthquake Reconnaissance Association; Paul Okubo, the Hawaiian Volcano Observatory; Barry Hirshorn, the Pacific Tsunami Warning Center; Jiro Sumada, the County of Hawaii Department of Public Works; Troy Kindred, Hawaii County Civil Defense Agency; Gen IInuma, Maui County Civil Defense Agency, Ernest Lau, State of Hawaii Department of Accounting and General Services; Afaq Sarwar, Sarwar Structural Engineering, John Dal Pino, Albert Chen, William Grogan, Lisbeth Blaisdell, Degenkolb Engineers; and William Holmes, Rutherford & Chekene and EERI Learning from Earthquakes Program Committee chair. A number or organizations were also involved in the post-earthquake reconnaissance: ATC-20 building safety engineers from the Structural Engineers Association of Hawaii – Bennett Fung, Clifford Lau, Kylie Yamatsuka, Ron Iwamoto, Gary Suzuki, Glenn Miyasato, Ian Robertson, Jeffrey Hanyu, James Walifish, Lee Takushi, Michael Kasamoto, Steven Heywood, Timothy Waite, Myles Shimokawa, and Randy Chu; the Hawaii State Earthquake Advisory Committee of State Civil Defense; and the U.S.
    [Show full text]
  • Last Revised 24 June 2013 Preferred Magnitudes of Selected Significant
    Last revised 24 June 2013 Preferred Magnitudes of Selected Significant Earthquakes Date Time† Place Lat. Long. Fatalities M MX‡ (M reference) January 23, 1556 Shaanxi (Shensi), China 34.5 109.7 830,000 ~8 February 5, 1663 22:30 Charlevoix-Kamouraska, Quebec, 47.6 -70.1 none ~7 M (Lamontagne et al, Canada (5:30 PM local time) 2008) August 17, 1668 Anatolia, Turkey 40.0 36.0 8,000 ~8 January 26, 1700 Cascadia subduction zone from No. CA to Vancouver Is. ~9 M (Satake et al, 1996) November 1, 1755 10:16 Lisbon, Portugal 36.0 -11.0 70,000 ~8.7 M I (Johnston, 1996) December 16, 1811 08:15 New Madrid, MO 36.6 -89.6 ~7.7 M I (Williams et al, 2011; (2:15 AM local time) Johnston, 1996; Hough et al, 2000; Bakun and Hopper, 2004) December 16, 1811 13:15 New Madrid, MO 36.6 -89.6 ~6.8-7.0 M I (Williams et al, 2011) (“dawn aftershock” -7:15 AM) January 23, 1812 15:15 New Madrid, MO 36.6 -89.6 ~7.5 M I (Williams et al, 2011; (9:15 AM local time) Johnston, 1996; Hough et al, 2000; Bakun and Hopper, 2004) February 7, 1812 09:45 New Madrid, MO 36.6 -89.6 ~7.7 M I (Williams et al, 2011; (3:45 AM local time) Johnston, 1996; Hough et al, 2000; Bakun and Hopper, 2004) June 2, 1823 08:00 South flank of Kilauea, HI 19.3 -155 ~7 M I (Klein and Wright, 2000) June 10, 1836 15:30 S San Francisco Bay region, CA 36.96 -121.37 ~6.5 M I (Bakun, 1999) June 1838 San Francisco Peninsula, CA 37.27 -122.23 ~6.8 M I (Bakun, 1999) January 5, 1843 02:45 Marked Tree, AR 35.5 -90.5 ~6.3 M I (Johnston, 1996) January 9, 1857 16:24 Fort Tejon, CA (San Andreas fault from Parkfield
    [Show full text]
  • Mineral, Virginia, Earthquake Illustrates Seismicity of a Passive
    GEOPHYSICAL RESEARCH LETTERS, VOL. 39, L02305, doi:10.1029/2011GL050310, 2012 Mineral, Virginia, earthquake illustrates seismicity of a passive-aggressive margin Emily Wolin,1 Seth Stein,1 Frank Pazzaglia,2 Anne Meltzer,2 Alan Kafka,3 and Claudio Berti2 Received 9 November 2011; revised 22 December 2011; accepted 23 December 2011; published 24 January 2012. [1] The August 2011 M 5.8 Mineral, Virginia, earthquake North America is a “passive” continental margin, along that shook much of the northeastern U.S. dramatically which the continent and seafloor are part of the same plate. demonstrated that passive continental margins sometimes The fundamental tenet of plate tectonics, articulated by have large earthquakes. We illustrate some general aspects Wilson [1965, p. 344], is that “plates are not readily of such earthquakes and outline some of the many unresolved deformed except at their edges.” Hence if plates were the questions about them. They occur both offshore and onshore, ideal rigid entities assumed in many applications, such as reaching magnitude 7, and are thought to reflect reactivation calculating plate motions, passive continental margins of favorably-oriented, generally margin-parallel, faults cre- should be seismically passive. ated during one or more Wilson cycles by the modern stress [3] In reality, however, large and damaging earthquakes field. They pose both tsunami and shaking hazards. How- occur along passive margins worldwide [Stein et al., 1979, ever, their specific geologic setting and causes are unclear 1989; Schulte and Mooney, 2005] (Figure 1). These earth- because large magnitude events occur infrequently, micro- quakes release a disproportionate share, about 25%, of the seismicity is not well recorded, and there is little, if any, net seismic moment release in nominally-stable continental surface expression of repeated ruptures.
    [Show full text]
  • Earthquake Safety Guidelines for Educational Facilities
    Earthquake Safety Guidelines for require an increased earthquake awareness Educational Facilities for parents, educators, school boards and students. Such an increase in awareness has By Rob Jackson, P. E. been a focus of the Earthquake Engineering Research Institute’s (EERI) Seismic Safety Every child has the right to attend school in of Schools Committee (EERI, 2012). safe buildings. The United States has been relatively lucky so far regarding school children and the occurrence of earthquakes. However, the United States cannot rely on such continued good fortune in the future. Governmental and educational leaders must fulfill their responsibilities for the safety of school children by implementing school safety programs that include the design and construction of seismically safe buildings. Such programs must emphasize seismic resistance and overall earthquake hazard resilience. Earthquake hazard mitigation is A typical unreinforced masonry high school in most readily accomplished through the the United States. (Wang, Y., EERI, 2012a) improved seismic design and construction of Similar advocacy efforts have impacted buildings, since “earthquakes don’t kill people, unsafe buildings do.” Earthquake policy across the United States. In California, hazard mitigation requires an increase in the positive steps have been taken to increase the prioritization and perceived value of seismic seismic safety of schools. The 1933 Long design within the project delivery systems of Beach earthquake resulted in passage of the the owners, construction managers, architects Field and Riley Acts. In California, no school and engineers who operate, design and child has been killed or seriously injured construct educational facilities in the United since 1933. However, no major California States.
    [Show full text]
  • United States Earthquakes, 1968 Open-File Report 84-968 Prepared in Cooperation with National Oceanic and Atmospheric Administra
    DEPARTMENT OF THE INTERIOR U.S. GEOLOGICAL SURVEY United States Earthquakes, 1968 By Jerry L. Coffman and William K, Cloud Open-File report 84-968 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 Contents Page Introduction __________________________________ 1 Earthquake information services ______________________ 1 Epicenter maps __________________________________________ 3 Teleseismic results ________________________________________ 3 Strong-motion seismograph network __________________________ 6 Magnitude and intensity ratings ______________________________ 6 Modified Mercalli intensity scale of 1931 ________________ 6 Earthquake history ____________________________ 7 Seismic risk map _________________________________________ 8 Summary of Earthquake Reports _______________________ 13 Earthquake activity in the various states _____________________ 13 Earthquake activity outside the United States ______________ 14 Northeastern region ______________________________ 14 Eastern region _____________________________ 14 Central region _________________________________________ 15 Western mountain region ____________________________________ 29 California and western Nevada ______________________ 31 Washington and Oregon _________________________ 52 Alaska _________________________________ 54 Hawaii __________________________________ 59 Panama Canal Zone ________________________________ 62 Puerto Rico __________________________________
    [Show full text]