1948 Desert Hot Springs earthquake

Earthquake in California May 2025 February 2025 1948 Desert Hot Springs earthquake USA California yes California 35.83 -115.43 Goodsprings 100 top Green pog.svg California 35.37 -119.02 Bakersfield 100 Green pog.svg California 34.05 -118.25 Los Angeles 100 left Green pog.svg California 34.95 -120.43 Santa Maria 100 left Green pog.svg California 32.79 -115.56 El Centro 100 right Green pog.svg California 32.72 -117.16 San Diego 100 left Green pog.svg California 33.77 -116.61 Bullseye1.png 40 250 right 1948-12-04 23:43:19 897665 ci9860350 1948 12 04 15:43:19 PST 6.4 w y 10 km on 33.77 N 116.62 W region:US-CA_type:event inline,title Strike-slip Coachella Valley Southern California United States 7 Yes (Indio Hills) Several injured The 1948 Desert Hot Springs earthquake occurred on December 4 at 3:43 p.m. Pacific Standard Time with a moment magnitude of 6.4 and a maximum Mercalli intensity of VII (Very strong). The shock was felt from the central coast of California in the north, and to Baja California in the south, and came at a time when earthquake research in southern California resumed following the Second World War. It was one of two events in the 20th century that have occurred near a complex region of the southern San Andreas Fault system where it traverses the San Gorgonio Pass and the northern Coachella Valley. Damage was not severe, but some serious injuries occurred, and aftershocks continued until 1957. Preface The United States' involvement in World War II brought about a lapse in earthquake research in California, due to scientists and other technicians being assigned defense-related work, and the ongoing process of using earthquake records to establish their epicenters eventually came to end. The Seismological Society of America cancelled their annual meetings and their Bulletin was reduced to half its normal size. Following the war, work resumed at the Caltech and Berkeley labs detecting local earthquakes to determine the location of active faults. By 1948, seismologist Charles Richter had determined that areas where small earthquakes were occurring did not necessarily mean that a stronger shock would take place at the same location in the future.California Earthquakes: Science, Risk, and the Politics of Hazard Mitigation https://archive.org/details/californiaearthq0000gesc registration C. Geschwind 2001 Johns Hopkins University Press 978-0801865961 119–122 Tectonic setting The San Gorgonio Pass is one of the largest irregularities of the San Andreas Fault system, where it branches into a group of discontinuous faults. The convoluted nature of fault strands make estimating the source characteristics of future events in that area challenging. Simultaneous rupture of multiple fault strands can produce exceptionally complex earthquakes, like the 1992 Landers earthquake, which was the result of sequential rupture of multiple strike-slip faults.Complexities of the San Andreas fault near San Gorgonio Pass: Implications for large earthquakes D. Yule K. Sieh Kerry Sieh 2003 Journal of Geophysical Research 108 2548 B11 10.1029/2001jb000451 2003JGRB..108.2548Y 10356/95547 free The San Andreas Fault system is similarly complex as it moves through the San Gorgonio Pass, with associated oblique/reverse faults that are actively uplifting San Gorgonio Mountain, the tallest peak in southern California. The 1986 North Palm Springs earthquake occurred to the west of the 1948 shock, and produced 9 km us of surface rupture on the Garnet Hill Fault or the Coachella strand of the Banning Fault. Together, these are the only historical shocks to occur on the portion of the San Andreas Fault System that lies south of the Cajon Pass.Active Faults of the World https://books.google.com/books?id=aQUgAwAAQBAJ Yeats R. 2012 Cambridge University Press 978-0-521-19085-5 100, 101 Earthquake The mainshock was recorded by few seismometers in the region. In contrast, the 1986 event occurred at a time when far more instruments were operating in southern California, and the additional volume of data that was generated provided a means for relocating and confirming the mechanism of faulting for the older event. The amplitude of the waveforms shown on the 1948 seismograms were 20–30% larger than those of the later shock. Like the 1986 event, the 1948 event was presumed to have occurred near the northwest-striking (and steeply-dipping) Banning Fault, which was relatively unknown at the time.Seismic behavior of the southern San Andreas fault zone in the northern Coachella Valley, California: Comparison of the 1948 and 1986 earthquake sequences http://bssa.geoscienceworld.org/content/86/5/1331.abstract C. Nicholson 1996 Bulletin of the Seismological Society of America 86 5 1338–1348 10.1785/BSSA0860051331 1996BuSSA..86.1331N 129962012 subscription A lack of surface ruptures from this predominantly strike-slip event is one element that contributed to preventing researchers from identifying the causative fault. The presence of shattered ground (very loose topsoil that appeared to have been "loosened by a shaking table") indicated to researchers that it probably originated in the hanging wall block between the Banning and Mission Creek Faults. Selected Mercalli intensities MMI Locations VII Desert Hot Springs, CA; Palm Springs, CA VI Los Angeles, CA; San Diego, CA V Arvin, CA; Barstow, CA IV El Centro, CA; Yuma, AZ III Goodsprings, NV; Bakersfield, CA Earthquake Intensity Database, National Geophysical Data Center Intensity The isoseismal map for this event is somewhat symmetrical, but with a significant east–west elongation that is aligned with the Transverse Ranges. The Mercalli intensity peaked at VII (Very strong) in the area around Desert Hot Springs. Intensity VI (Strong) effects were observed in Los Angeles, where damage was slight and several hundred automatic gas shutoff valves were tripped, especially in Monterey Park (just to the east of Los Angeles). At roughly the same distance from the epicenter, San Diego had more intense effects than El Centro did. Intensity VI was felt in San Diego, while El Centro was marked as I–IV (Not Felt–Light). This was likely due to a difference in local geological features, and the attenuation factor along the path to each area, sometimes called "earthquake shadows".The Desert Hot Springs earthquakes and their tectonic environment http://bssa.geoscienceworld.org/content/48/4/315.abstract?sid=4005ad92-8984-49e1-b33d-3aa8cd562a96 C.F. Richter Charles Francis Richter C.R. Allen Clarence Allen (geologist) J. M. Nordquist 1958 Bulletin of the Seismological Society of America 48 316–319, 326, 327 Damage The shock was felt as far north as Santa Maria and south into northern Baja California, and was described by seismologists as having been stronger than the 1933 Long Beach earthquake that heavily affected southern California, but no one was killed and only relatively minor damage occurred. A few injuries, some serious, occurred at the Palm Springs Theater during the rush to evacuate the building, and another man was injured by falling merchandise and required hospitalization. In Downtown Los Angeles, buildings swayed, windows were broken, and cracks appeared in buildings. Similar types of damage was also present in Twentynine Palms, El Centro, and Yucca Valley.Quake shakes southland; Desert towns hardest hit December 5, 1948 Los Angeles Times Aftershocks A late 1950s study of the event included details on aftershocks that were greater than 3.0 l y. In this range, there were 18 aftershocks on the first day (including eight within the first hour) and 12 the following day. These events continued to occur every day for nearly a week, at which time they began tapering off and became less of a daily occurrence. By late December, there were one per day or less, with 60 events through the remainder of the year. In 1949 there were far less, with 16 events altogether. The last event that was mentioned in the study occurred in January 1957. See also List of earthquakes in 1948 List of earthquakes in California List of earthquakes in the United States References ISC-GEM Global Instrumental Earthquake Catalogue (1900–2013) http://www.isc.ac.uk/iscgem/index.php ISC 2017 International Seismological Centre Version 4.0 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 84, 141 External links Desert Hot Springs Earthquake – Southern California Earthquake Data Center 897665 1948 Category:1948 earthquakes Category:Desert Hot Springs, California Category:Coachella Valley Category:Organized events in Riverside County, California Category:Colorado Desert Category:1948 in California Category:1948 natural disasters in the United States Category:December 1948 in the United States