1990 Upland earthquake

Earthquake in Southern California May 2025 February 2025 1990 Upland earthquake February 28, 1990 23:43:37 UTC 15:43:37 local USA California yes California 36.18 -115.14 Las Vegas 100 left Green pog.svg California 34.43 -119.72 Santa Barbara 100 left Green pog.svg California 32.72 -117.16 San Diego 100 left Green pog.svg California 34.16 -117.73 Bullseye1.png 40 250 right 1990-02-28 23:43:36 380064 ci1053635 5.7 w y VII 1.05 g 10 km on 34.16 -117.73 inline,title Strike-slip San Jose Fault Greater Los Angeles Area Southern California United States $12.7 million 30 injured The 1990 Upland earthquake occurred at 15:43:37 local time 23:43:37 UTC on February 28 with a moment magnitude of 5.7 and a maximum Mercalli Intensity of VII (Very strong). This left-lateral strike-slip earthquake occurred west of the San Andreas Fault System and injured thirty people, with total losses of $12.7 million. Many strong motion instruments captured the event, with an unexpectedly high value seen on water tank near the epicentral area. Tectonic setting In the Transverse Ranges west of the right-lateral San Andreas Fault System, some faults exhibit left-lateral slip, including some at the boundary of the Los Angeles Basin and the Transverse Ranges.Active Faults of the World https://books.google.com/books?id=aQUgAwAAQBAJ Yeats R. 2012 Cambridge University Press 978-0521190855 107–110 Earthquake While several examinations of earthquake focal mechanisms in the Upland area showed both thrust and strike-slip faulting on opposite ends of the San Jose Fault, the mechanism of the 1990 event showed pure left-lateral motion on a steeply-dipping (70°) and northeast-striking fault. Field investigations revealed that the bilateral rupture did not reach the surface.The 1988 and 1990 Upland Earthquakes: Left-Lateral Faulting Adjacent to the Central Transverse Range http://authors.library.caltech.edu/37194/1/jgrb8176.pdf E. Hauksson L. Jones Lucy Jones 1991 Journal of Geophysical Research 96 B5 8144, 8151 10.1029/91jb00481 1991JGR....96.8143H Strong motion Peak ground acceleration The shock was felt from Santa Barbara in the west and to Las Vegas in the east. It was also felt in Ensenada, Baja California and it triggered 82 strong motion instruments at distances of 3 - 76 km us. Typical ground accelerations were around 0.1 g at distances of up to 30 km on, but some closer stations had significantly higher responses.Strong-motion recordings from the ML=5.5 Upland, California earthquake of February 28, 1990 https://pubs.er.usgs.gov/publication/ofr90311 E. C. Etheredge A. V. Acosta L. J. Foote D. A. Johnson R. P. Maley R. L. Porcella J. C. Switzer 1990 Open-File Report 90-311 United States Geological Survey 1–5 Damage Rockslides left some roads closed in the San Gabriel Mountains and Pomona city hall was heavily damaged. In Claremont some buildings were damaged, but only one building in Upland's historic downtown area was tagged for non-occupation. Those that were injured suffered cuts and bruises (mainly from falling objects) but two men were injured as a result of a landslide.Quake Damage at Least $20 Million : New Slide Recloses Mt. Baldy Road; Aftershocks Continue https://www.latimes.com/archives/la-xpm-1990-03-01-mn-2462-story.html J. Warren K. Roderick March 1, 1990 Los Angeles TimesQuake Hits Vast Area of Southland : Seismic: Epicenter near Upland. Some damage but only minor injuries reported. Estimated strength of temblor varies from 5.5 to 6.1 https://www.latimes.com/archives/la-xpm-1990-03-01-mn-2189-story.html E. Malnic L. Sahagun March 1, 1990 Los Angeles Times See also California List of earthquakes in 1990 List of earthquakes in California List of earthquakes in the United States References ISC-GEM Global Instrumental Earthquake Catalogue (1900–2012) http://www.isc.ac.uk/iscgem/index.php ISC 2016 International Seismological Centre Version 3.0 Significant Earthquake Database https://www.ngdc.noaa.gov/nndc/struts/form?t=101650&s=1&d=1 https://web.archive.org/web/20060929000601/http://www.ngdc.noaa.gov/nndc/struts/form?t=101650&s=1&d=1 dead September 29, 2006 National Geophysical Data Center / World Data Service (NGDC/WDS) National Geophysical Data Center, NOAA 10.7289/V5TD9V7K 1972 Data Set PAGER-CAT Earthquake Catalog https://earthquake.usgs.gov/static/lfs/data/pager/catalogs/ September 4, 2009 United States Geological Survey Version 2008_06.1 External links M5.5 – 6km NNE of Claremont, CA – United States Geological Survey 380064 Category:1990 earthquakes Category:Earthquakes in California Category:1990 in California Category:Upland, California Category:1990 natural disasters in the United States