1986 North Palm Springs earthquake

Earthquake in Southern California 1986 Chalfant Valley earthquake January 2023 January 2023 1986 North Palm Springs earthquake USA California yes California 35.62 -117.67 Ridgecrest 100 left Green pog.svg California 34.03 -118.75 Malibu 100 left Green pog.svg California 33.21 -117.33 Oceanside 100 left Green pog.svg California 35.12 -114.59 Bullhead City 100 left Green pog.svg California 36.18 -115.14 Las Vegas 100 top Green pog.svg California 32.69 -114.62 Yuma 100 Green pog.svg California 37.36 -118.4 Bishop 100 left Green pog.svg California 34.00 -116.61 Bullseye1.png 40 250 right 1986-07-08 09:20:44 490261 iscgem490261 1986 07 08 02:20:44 PDT 6.0 w y 10 km on 34.02 N 116.76 W region:US-CA_type:event inline,title Strike-slip Inland Empire Southern California United States $4.5–6 million VII 0.778 g 29–40 injured The 1986 North Palm Springs earthquake occurred on July 8 at 02:20:44 local time 09:20:44 Universal Coordinated Time with a moment magnitude of 6.0 and a maximum Mercalli Intensity of VII (Very strong). The shock occurred in a complex setting along the San Andreas Fault Zone where it bisects San Gorgonio Mountain and San Jacinto Peak at the San Gorgonio Pass and was the first in a series of three earthquakes that affected southern California and the northern Owens Valley in July 1986. Numerous strong motion instruments recorded the event, one of which showed relatively high accelerations. Between 29 and 40 people were injured, and financial losses were estimated to be in the range of $4.5–6 million. Preface July 1986 was an unusually active month for moderate to strong earthquakes in California, with three events occurring in less than two weeks. Each had mild to moderate effects and began on July 8 with the event near Palm Springs. The second event was a s y 5.8 shock that occurred off the coast of Oceanside on July 13. While the earthquake off the southern California coast occurred in an area thought to be capable of generating a tsunami, the earthquake near Palm Springs occurred on a portion of the southern San Andreas Fault system that has been designated a seismic gap and is a likely location for a very large future earthquake. The Chalfant Valley earthquake occurred on July 21 along the White Mountains Fault Zone near Bishop.Source mechanisms of three moderate California earthquakes of July 1986 http://bssa.geoscienceworld.org/content/78/6/1907.abstract J. Pacheco J. Nabelek December 1, 1988 Bulletin of the Seismological Society of America 78 6 1907–1909 Tectonic setting The San Andreas Fault (SAF) spans nearly the length of California, where much it is clearly identifiable for much of its length, especially from San Francisco to near Cajon Pass. There, the fault splays into several branches. Several unusual characteristics are displayed further to the southeast in the area of the San Gorgonio Pass. There are no lateral stream offsets (that are associated with strike-slip faulting) near the pass like there are along other segments (one researcher indicated that thrust faulting was the dominant type of fault displacement at the pass). There are no great earthquakes that are known to have occurred at the pass, where the main trace of the SAF is marked by numerous sag ponds and north-facing scarps. The Banning Fault lies about two miles to the south of these features.The San Andreas Fault Zone in San Gorgonio Pass, California C. R. Allen Clarence Allen (geologist) 1954 Dissertation (Ph.D.) California Institute of Technology 1, 4, 7, 92, 93, 96 10.7907/54GN-M254 phd August 27, 2019 August 15, 2020 https://web.archive.org/web/20200815130307/https://thesis.library.caltech.edu/1788/ https://thesis.library.caltech.edu/1788/ live Earthquake thumb|Strong ground motion map for the event|alt=Map of the epicenter region showing varying shaking intensities Early research indicated that the Banning Fault comprises three segments and that the nearly-parallel Garnet Hill Fault lies just to the south. The epicenter of the July 8 earthquake was located in this convoluted area of faults between two segments of the Banning Fault and the Mission Creek strand of the San Andreas Fault, about 25 km flip northwest of where these two faults converge to form the Coachella Valley segment of the SAF. The focal mechanism (as defined by first motions) showed pure right-lateral strike-slip on a fault trending west-northwest that dipped to the north at 45°. As many of the aftershocks and previous events in the area showed oblique-reverse motion, researchers did not exclude the possibility that the rupture started as horizontal motion, then transitioned into movement that included some vertical motion.The North Palm Springs, California, earthquake sequence of July 1986 http://www.bssaonline.org/content/76/6/1830.extract L. M. Jones Lucy Jones L. K. Hutton Kate Hutton D. D. Given C. R. Allen December 1, 1986 Bulletin of the Seismological Society of America 76 6 1830–1833 10.1785/BSSA0760061830 1986BuSSA..76.1830J June 13, 2015 September 23, 2015 https://web.archive.org/web/20150923194934/http://www.bssaonline.org/content/76/6/1830.extract dead subscription Damage In North Palm Springs, four homes and 16 businesses were destroyed, and an additional 100 mobile homes and 100 businesses were damaged. In Whitewater Canyon, chimneys fell and three homes were destroyed; ceramic columns were broken and a transformer was displaced at the Devers electrical substation. The Windy Point Bridge was displaced on I-10 northwest of Palm Springs, causing a separation of the deck and abutment. Other temporary roadway closures included State Route 111, which was closed until the following evening, and State Route 74 and State Route 243 that were reopened later in the day. State Route 62, which crosses the Banning and Mission Creek faults, was not immediately reopened due to buckled pavement. The California Aqueduct was damaged at several locations and water had to be diverted into a lake bed, and up to 80,000 people lost power for a portion of the day. Two fires in Riverside County caused serious damage, including a glass company that sustained $45,000 in damage, and several other brush fires.Strong Quake in Desert Rolls Across Southland : 6.0 Temblor Awakens Residents in Wide Area; Damage Limited by Remote Site of Epicenter https://www.latimes.com/archives/la-xpm-1986-07-09-mn-14306-story.html Roxane Arnold Eric Malnic July 9, 1986 Los Angeles Times June 13, 2015 June 16, 2015 https://web.archive.org/web/20150616170140/http://articles.latimes.com/1986-07-09/news/mn-14306_1_palm-springs-area live Strong motion The shock was captured by strong motion stations that were operated by the United States Geological Survey, California Division of Mines and Geology, University of Southern California and Kinemetrics Inc., a private company. Altogether, the networks comprised about 75 stations, mainly including ground response stations, but also included 17 buildings, nine dams, a power plant, and a freeway interchange. The stations were triggered at distances of up to 180 km flip, with a strong motion duration of greater than three seconds at five of the closest stations. The strongest acceleration (0.778 g) occurred at the North Palm Springs Post Office on the vertical axis.Strong motion data from the July 8, 1986 North Palm Springs earthquake and its aftershocks https://pubs.er.usgs.gov/publication/ofr87155 R. L. Porcella E. C. Etheredge R. P. Maley J. C. Switzer Strong-motion data from the July 8, 1986 North Palm Springs earthquake and aftershocks 1987 Geological Survey Open File Report 87-155 United States Geological Survey 1–5, 28 10.3133/ofr87155 August 28, 2017 June 16, 2015 https://web.archive.org/web/20150616012832/http://pubs.er.usgs.gov/publication/ofr87155 live Intensity The maximum intensity for the event was VII (Very strong). At Desert Hot Springs, effects aligned with this rating were broken underground pipes (including a 5-inch water main) and filing cabinets that were knocked over at city hall. At the Devers substation near North Palm Springs, 75 percent of the ceramic lightning arrestors and circuit breakers were damaged, and a 650,000 lb. transformer was dislocated 10 inches. A building collapsed at a drug and alcohol recovery facility and the White Water overpass was damaged due to lateral movement at its south abutment in Palm Springs. Broken glass and cracks in walls and concrete columns (some severe) were also widespread there.United States earthquakes, 1986 https://pubs.usgs.gov/bul/2089/report.pdf C. W. Stover L. R. Brewer 1994 U.S. Geological Survey Bulletin 2089 United States Government Printing Office 32–41 October 6, 2017 May 1, 2017 https://web.archive.org/web/20170501002621/https://pubs.usgs.gov/bul/2089/report.pdf live Intensity VI (Strong) effects were widespread, from La Jolla and Pacific Beach area near San Diego to Seal Beach in the Los Angeles area that were deemed to qualify. The effects at this level included cracked walls and windows and small landslides, and were more prevalent in the Banning Pass and Palm Springs Area areas. The area of perceptibility for the mainshock was large (130,500 km2), from Malibu and Ridgecrest in California, to Bullhead City and Yuma in Arizona, and Las Vegas in southern Nevada. See also California List of earthquakes in 1986 List of earthquakes in California References ISC-GEM Global Instrumental Earthquake Catalogue (1900–2009) http://www.isc.ac.uk/iscgem/index.php ISC January 19, 2015 International Seismological Centre Version 2.0 June 13, 2015 November 25, 2016 https://web.archive.org/web/20161125091901/http://www.isc.ac.uk/iscgem/index.php live PAGER-CAT Earthquake Catalog https://earthquake.usgs.gov/static/lfs/data/pager/catalogs/ September 4, 2009 United States Geological Survey Version 2008_06.1 December 20, 2017 https://web.archive.org/web/20161004150402/http://earthquake.usgs.gov/data/pager/catalogs/ October 4, 2016 dead Stover C. W. Coffman J. L. Seismicity of the United States, 1568–1989 (Revised) – U.S. Geological Survey Professional Paper 1527 https://books.google.com/books?id=bY0KAQAAIAAJ 1993 United States Government Printing Office 97, 177 October 29, 2016 April 13, 2019 https://web.archive.org/web/20190413193951/https://books.google.com/books?id=bY0KAQAAIAAJ live External links North Palm Springs Earthquake – Southern California Earthquake Data Center Historic Earthquakes: North Palm Springs, California – United States Geological Survey M 6.0 – 6km SSW of Morongo Valley, CA – United States Geological Survey 490261 Category:Earthquakes in California Category:1986 earthquakes Category:1986 in California