1983 Coalinga earthquake

Earthquake affecting Central California 1983 Coalinga earthquake USA California California 34.05 -118.25 Los Angeles 100 Green pog.svg California 40.42 -120.65 Susanville 100 left Green pog.svg California 36.14 -120.36 Coalinga 100 left Green pog.svg California 36.0 -120.13 Avenal 100 Green pog.svg California 36.23 -120.31 Bullseye1.png 40 290 right yes 1983-05-02 23:42:37 575305 nc1091100 1983 5 2 4:42 p.m 6.2 w y US$10 millionStover Coffman 1993 171 5.9 w y July 22 at 02:39Stover Coffman 1993 97, 175 10 km mi 0 us 36.23 N 120.31 WStover Coffman 1993 96 Blind thrust 8 Central California United States Yes 94 injured Californiaearthquake1983.jpg A destroyed building on 5th Street in Coalinga The 1983 Coalinga earthquake struck at 4:42 p.m. Monday, May 2 of that year, in Coalinga, California.Associated Press, "Coalinga Earthquake: It Might Have Been Worse Somewhere Else", Santa Cruz Sentinel, May 4, 1983, page 38 The shock was felt from the Greater Los Angeles Area north to Susanville in Lassen County, and between the Pacific Coast and western Nevada. More than 5,000 aftershocks were recorded through July 31, of which 894 had a magnitude of 2.5 or larger. It measured 6.2 on the moment magnitude scale and had a maximum Mercalli intensity of VIII (Severe). Earthquake The Coalinga quake was caused by an 0.5-meter uplift of an anticline ridge northeast of Coalinga, but surface faulting was not observed. Ground and aerial reconnaissance immediately after the quake revealed ground cracks and fissures within about 10 km mi us of the epicenter, none of which appeared to represent movement on deeply rooted fault structures. About five weeks later, on June 11, an aftershock caused surface faulting about 12 km mi on northwest of Coalinga.https://earthquake.usgs.gov/regional/states/events/1983_05_02.php United States Geological Survey Earthquake's destruction https://web.archive.org/web/20080626170722/http://earthquake.usgs.gov/regional/states/events/1983_05_02.php 26 June 2008 live Damage The earthquake caused an estimated $10 million in property damage (according to the American Red Cross) and injured 94 people. Damage was most severe in Coalinga, where the eight-block downtown commercial district was almost destroyed. Here, buildings having unreinforced brick walls sustained the heaviest damage. Newer buildings, such as the Bank of America and the Guarantee Savings and Loan, only sustained superficial damage. The most significant damage outside the Coalinga area was at Avenal, 31 km mi us southeast of the epicenter. A disaster assessment by the American Red Cross listed the following statistics on damage in the area: almost destroyed – 309 single-family houses and 33 apartment buildings; major damage – 558 single-family houses, 94 mobile homes, and 39 apartment buildings; and minor damage – 811 single-family houses, 22 mobile homes, and 70 apartment buildings. Most public buildings, including the City Hall, hospital, schools, fire house, post office, and police station, only sustained minor damage. right USGS Shakemap - 1983 Coalinga earthquake (mainshock).jpg USGS Shakemap - 1983 Coalinga earthquake (aftershock).jpg USGS ShakeMaps for the mainshock (left) and the July 22 aftershock Six bridges of 60 in the area sustained measurable structural damage, which consisted of hairline cracks and spalling at the top of the support columns, fracturing and displacement of wing walls and parapets, and settlement of fill. All public utilities were damaged, but the water system continued to function despite many leaks in its transmission piping. Gas was shut off for several days because of broken piping and leaks, but only temporary interruptions of electric and telephone services were reported. One large section of old concrete sewerage west of the downtown area partially collapsed but continued to function. In the oil fields near Coalinga, surface facilities such as pumping units, storage tanks, pipelines, and support buildings were all damaged to some degree. One oil company administration building, about 7 km mi on north of Coalinga, sustained major structural damage, and its two brick chimneys toppled. Subsurface damage, including collapsed or parted well casing, was observed on fourteen of 1,725 active wells. Ground effects The earthquake triggered thousands of rock falls and rock slides as far as 34 km mi on northwest, 15 km mi on south, and 26 km mi on southwest of the epicenter. Only a few slope failures occurred east of the epicenter because of the absence of steep slopes in that direction. Aftermath The California Seismic Safety Commission investigated the temblor, provided funding and expert technical assistance for planning and reconstruction and published a report on the quake.Senate Bill No. 1278 Chapter 532 An act to amend Sections of the Government Code relating to the Seismic Safety Commission. https://web.archive.org/web/20080807182302/http://www.seismic.ca.gov/pdf.files/seismic_safety_act.pdf 2008-08-07 (September 28, 2006) Coalinga recovered 98 percent of its expenses in repairing and rebuilding public buildings at a time when an 85 percent recovery was considered a success.Borba, Jeanie; Diaz, Sam. (May 2, 1993) The Fresno Bee. Coalinga – The town the quake built. Section: Telegraph; p. A1. The Coalinga earthquake suggested to geologists that the state of California was in worse seismological danger than had been thought. The pace of earthquake activity along the Pacific coast was identified as a relevant subject for further study, and the investigation of earthquakes stemming from unknown faults caused concern.Blakeslee, Sandra. "Lesson of Coalinga: California Seems in Still Greater Peril," The New York Times. May 24, 1983. California officials said that a predicted great quake would do far more damage than this one and that if it struck in a densely populated area the damage would be incalculable.Lessons of 'Moderate' Coast Earthquake https://select.nytimes.com/search/restricted/article?res=F70813FD395C0C778CDDAC0894DB484D81 Robert Lindsey May 4, 1983 The New York Times See also California List of earthquakes in 1983 List of earthquakes in California List of earthquakes in the United States References Active Faults of the World https://books.google.com/books?id=aQUgAwAAQBAJ Yeats R. 2012 Cambridge University Press 978-0-521-19085-5 95 Sources Effects of the 1983 Coalinga, California, earthquake on creep along the San Andreas fault http://bssa.geoscienceworld.org/content/75/2/475.abstract G. M. Mavko S. Schulz B. D. Gary M. Mavko Brown 1983 Bulletin of the Seismological Society of America 75 2 475–489 The 1983 Coalinga, California Earthquakes, CDMG Special Publication 66 Strong Motion Data From the Coalinga, California Earthquakes and Aftershocks OSMS 83-04, California Strong Motion Instrumentation Program http://www.consrv.ca.gov/cgs/smip/docs/reports/Other/Pages/OSMS83-04.aspx 1983 A. F. Shakal J. T. Ragsdale California Division of Mines and Geology 2014-05-11 2014-05-12 https://web.archive.org/web/20140512232449/http://www.consrv.ca.gov/cgs/smip/docs/reports/Other/Pages/OSMS83-04.aspx dead C. W. Stover J. L. Coffman Seismicity of the United States, 1568–1989 (Revised) https://books.google.com/books?id=bY0KAQAAIAAJ U.S. Geological Survey professional paper 1527 1993 United States Government Printing Office Further reading The Coalinga Anticline and the Coalinga Earthquake of 1983 – San Joaquin Valley Geology https://earthquake.usgs.gov/regional/states/events/1983_05_02.php United States Geological Survey External links 575305 Category:1983 earthquakes 1983 Earthquake 1983 Category:History of Fresno County, California Category:History of the San Joaquin Valley Category:Buried rupture earthquakes Category:1983 in California