  Palm Springs Los Angeles  | |
| UTC time | 1992-06-28 11:57:35 |
|---|---|
| ISC event | 289086 |
| USGS-ANSS | ComCat |
| Local date | June 28, 1992 |
| Local time | 4:57:35 am PDT |
| Magnitude | 7.3 Mw |
| Depth | 0.68 miles (1.09 km) |
| Epicenter | 34°13′01″N 116°25′59″W / 34.217°N 116.433°W[1] |
| Type | Strike-slip |
| Areas affected | Southern California United States |
| Total damage | $92 million [2] |
| Max. intensity | IX (Violent) |
| Foreshocks | 6.1 Mw April 23 at 4:51 [3] |
| Casualties | 3 killed 400+ injured |
The 1992 Landers earthquake occurred on June 28 near the town of Landers, California with a moment magnitude of 7.3 and a maximum perceived intensity of IX (Violent) on the Modified Mercalli Intensity Scale. The quake was the largest earthquake to have occurred in the contiguous United States in 40 years and was part of a sequence of seismic events in the Mojave region that encompassed a several month period.
Eastern California shear zone
edit.[4]
Earthquake sequence
editJoshua Tree earthquake
editThe Landers mainshock was preceded by the 6.1 magnitude Joshua Tree earthquake on April 23, 1992, which was located to the south of the future Landers epicenter.[3]
Landers earthquake
edit
At 04:57 local time (11:57 UTC) on June 28, 1992, a large quake awoke much of Southern California. The shaking lasted for two to three minutes. Although this earthquake was a lot more powerful than the 1994 Northridge earthquake, its location out in the Mojave Desert meant that damage and loss of life were significantly less than what they could have been.
The earthquake was a right-lateral strike-slip event, and involved the rupture of several different faults over a length of 75 to 85 km (47 to 53 mi). The names of those that were involved are the Johnson Valley, Kickapoo (also known as Landers), Homestead Valley, Homestead/Emerson, Emerson Valley and Camp Rock faults.
Damage
editDamage to the area directly surrounding the epicenter was severe. Roads were buckled, buildings and chimneys collapsed. There were also large surface fissures. To the west in the Los Angeles Basin damage was much less severe. The majority of damage in the Los Angeles area involved items which had fallen off shelves. Unlike the 1994 Northridge earthquake nineteen and a half months later, no freeway bridges collapsed because of the epicenter's remote location. Electricity was disabled to thousands of residents, but was generally restored within two to three hours. There was also some damage to homes from water displaced from swimming pools.
Loss of life in this earthquake was minimal. Two people died as a result of heart attacks. A 3-year-old boy from Massachusetts, who was visiting Yucca Valley with his parents, died when bricks from a chimney collapsed into a living room where he was sleeping [5] and more than 400 people sustained injuries as a result of the earthquake.
Strong motion
edit.[6]
.[7]
Surface faulting
edit.[8]
Hydrologic effects
edit.[9]
Triggered seismicity
edit.[10]
Big Bear earthquake
editThe 6.5 magnitude Big Bear earthquake, which hit about three hours later after the Landers mainshock, was originally considered an aftershock. However, the United States Geological Survey determined that this was a separate, but related, earthquake. These two earthquakes are considered a regional earthquake sequence, rather than a main shock and aftershock.
Little Skull Mountain earthquake
editThe 5.7 magnitude Little Skull Mountain (LSM) earthquake the following day, June 29, 1992, at 10:14 UTC near Yucca Mountain, Nevada, is also considered part of the regional sequence and may have been triggered by surface wave energy produced by the Landers earthquake. Foreshock activity, in the form of a significant increase in micro-earthquakes, was observed at Little Skull Mountain following the Landers earthquake, and the activity continued until the main LSM earthquake.[11]
References
edit- ^ "Landers Earthquake". Southern California Earthquake Data Center. Archived from the original on March 5, 2014. Retrieved August 15, 2014.
- ^ Cite error: The named reference
earthquake1was invoked but never defined (see the help page). - ^ a b Hauksson, E.; Jones, L. M.; Hutton, K.; Eberhart-Phillips, D. (1993). "The 1992 Landers Earthquake Sequence: Seismological observations". Journal of Geophysical Research. 98 (B11). American Geophysical Union: 19835–19858.
- ^ Yeats, Robert (2012), Active Faults of the World, Cambridge University Press, pp. 122–124, ISBN 978-0521190855
- ^ Gebe Martinez (June 30, 1992). "The Landers and Big Bear Quakes : Death of Toddler Touches Many in Close-Knit Town". Los Angeles Times.
- ^ Cramer, C. H.; Darragh, R. B. (1994), "Peak accelerations from the 1992 Landers and Big Bear, California, earthquakes", Bulletin of the Seismological Society of America, 84 (3), Seismological Society of America: 589–595
- ^ Fenves, G. L. (1997), Utilization of strong-motion data from bridges and dams, California Division of Mines and Geology, pp. 111–127
- ^ Murbach, D. (1994), Characteristics of the 1992 fault rupture adjacent to distressed structures, Landers, California, Earthquake Engineering Research Institute
- ^ Roeloffs, E. A.; Danskin, W. R.; Farrar, C. D.; Galloway, D. L.; Hamlin, S. N.; Quilty, E. G.; Quinn, H. M.; Schaefer, D. H.; Sorey, M. L.; Woodcock, D. E., Hydrologic effects associated with the June 28, 1992 Landers, California, earthquake sequence (PDF), Open File Report 95-42, United States Geological Survey
- ^ Hill, D. P.; Reasenberg, P. A.; Michael, A.; Arabaz, W. J.; Beroza, G.; Brumbaugh, D.; Brune, J. N.; Castro, R.; Davis, S.; dePolo, D.; Ellsworth, W. L.; Gomberg, J.; Harmsen, S.; House, L.; Jackson, S. M.; Johnston, M. J. S.; Jones, L.; Keller, R.; Malone, S.; Munguia, L.; Nava, S.; Pechmann, J. C.; Sanford, A.; Simpson, R. W.; Smith, R. B.; Stark, M.; Stickney, M.; Vidal, A.; Walter, S.; Wong, V.; Zollweg, J. (1993), "Seismicity Remotely Triggered by the Magnitude 7.3 Landers, California, Earthquake", Science, 260 (5114), American Association for the Advancement of Science : 1617–1623
{{citation}}: Cite has empty unknown parameter:|1=(help) - ^ Smith, K. D.; Brune, J. N.; dePolo, D.; Savage, M. K. (2000). "Geologic and Geophysical Characterization Studies of Yucca Mountain, Nevada, A Potential High-Level Radioactive-Waste Repository" (PDF). U.S. Geological Survey Digital Data Series 58. United States Geological Survey. ISBN 9780607948226.
{{cite web}}:|chapter=ignored (help)
- Sources
- Berryman, K. (1992), "Reconnaissance field investigation of the Landers earthquake (Ms 7.5) of June 28, 1992, San Bernardino County, California, USA" (PDF), Bulletin of the New Zealand National Society for Earthquake Engineering, 25 (3), New Zealand Society for Earthquake Engineering: 230–241
- Rymer, M. J. (2000), "Triggered Surface Slips in the Coachella Valley Area Associated with the 1992 Joshua Tree and Landers, California, Earthquakes", Bulletin of the Seismological Society of America, 90 (4), Seismological Society of America: 832–848
External links
edit- Landers Earthquake – Southern California Earthquake Data Center
- Big Bear Earthquake – Southern California Earthquake Data Center
- Historic Earthquakes – United States Geological Survey