Related Research Articles
The Modified Mercalli intensity scale measures the effects of an earthquake at a given location. This is in contrast with the seismic magnitude usually reported for an earthquake.
The 1872 Owens Valley earthquake – also known as the Lone Pine earthquake – struck on March 26 at 02:30 local time in the Owens Valley, with the epicenter near the town of Lone Pine. Its magnitude has been estimated at Mw 7.4 to 7.9, with a maximum Mercalli Intensity of X (Extreme). It was one of the largest earthquakes to hit California in recorded history and was similar in size to the 1906 San Francisco earthquake. Twenty-seven people were killed and fifty-six were injured.
The 1868 Hayward earthquake occurred in the San Francisco Bay Area, California, United States on October 21. With an estimated moment magnitude of 6.3–6.7 and a maximum Mercalli intensity of IX (Violent), it was the most recent large earthquake to occur on the Hayward Fault Zone. It caused significant damage and a number of deaths throughout the region, and was known as the "Great San Francisco earthquake" prior to the 1906 San Francisco earthquake and fire.
The 1915 Pleasant Valley earthquake occurred at 22:53:21 on October 2 in north-central Nevada. With a moment magnitude of 6.8, a surface wave magnitude of 7.7, and a maximum Mercalli intensity of X (Extreme), it was the strongest earthquake ever recorded in the state.
The 1940 New Hampshire earthquakes struck on December 20 and again on December 24. Both shocks had an estimated Ms magnitude of 5.6, and a maximum Mercalli intensity of VII. These doublet earthquakes were the largest to hit the state in several hundred years. Damage included minor fractures or knocked over chimneys in a zone extending through New Hampshire and four other states: Maine, New York, Vermont and Massachusetts.
The 1940 El Centro earthquake occurred at 21:35 Pacific Standard Time on May 18 in the Imperial Valley in southeastern Southern California near the international border of the United States and Mexico. It had a moment magnitude of 6.9 and a maximum perceived intensity of X (Extreme) on the Mercalli intensity scale. It was the first major earthquake to be recorded by a strong-motion seismograph located next to a fault rupture. The earthquake was characterized as a typical moderate-sized destructive event with a complex energy release signature. It was the strongest recorded earthquake in the Imperial Valley, causing widespread damage to irrigation systems and killing nine people.
The 1892 Laguna Salada earthquake occurred at 23:20 Pacific Standard Time on February 23. It had an estimated moment magnitude of 7.1–7.2 and a maximum perceived intensity of VIII (Severe). The shock was centered near the Mexico–United States border and takes its name from a large dry lake bed in Baja California, Mexico. There were no reported casualties, but the event affected the then largely-uninhabited areas of northern Mexico and Southern California.
The 1812 San Juan Capistrano earthquake, also known simply as the Capistrano earthquake or the Wrightwood earthquake, occurred on December 8 at 15:00 UTC in Alta California. At the time, this was a colonial territory of the Spanish Empire. Damage occurred at several of the missions in the region of Pueblo de Los Ángeles, including Mission San Gabriel Arcángel and Mission San Juan Capistrano, where 40 parishioners were killed during the collapse of a church at an early morning service. Tree ring and paleoseismic evidence show that there is a strong likelihood that the earthquake originated along the Mojave segment of the San Andreas Fault near Wrightwood, but other faults have been suggested as the cause.
The 1975 Hawaii earthquake occurred on November 29 with a moment magnitude of 7.7 and a maximum Mercalli intensity of VIII (Severe). The shock affected several of the Hawaiian Islands and resulted in the deaths of two people and up to 28 injured. Significant damage occurred in the southern part of the Big Island totalling $4–4.1 million, and it also triggered a small brief eruption of Kilauea volcano.
The 1892 Vacaville–Winters earthquakes occurred in northern California as a large doublet on April 19 and April 21. Measured on a seismic scale that is based on an isoseismal map or the event's felt area, the 6.4 Mla and 6.2 Mla events were assigned a maximum Mercalli intensity of IX (Violent), and affected the North Bay and Central Valley areas. The total damage was estimated to be between $225,000 and 250,000 and one person was killed. No evidence of fault movement on the surface of the ground was observed as a result of either of the strong shocks. Both occurred in the domain of the San Andreas strike-slip system of faults, but their focal mechanism is uncertain.
The 1918 San Jacinto earthquake occurred in extreme eastern San Diego County in Southern California on April 21 at 14:32:29 local time. The shock had a moment magnitude of 6.7 and a maximum Mercalli intensity of IX (Violent). Several injuries and one death occurred with total losses estimated to be $200,000.
The 1932 Eureka earthquake occurred on June 6 at 00:44:26 local time along the northern coastal area of California in the United States. With a moment magnitude of 6.4 and a maximum Mercalli intensity of VIII (Severe), this earthquake left one person dead from a falling chimney and several injured. The shock was the largest in the area since 1923 and was felt in southern Oregon and northern California.
The 1973 Point Mugu earthquake occurred at 06:45:57 local time on February 21 in the Point Mugu area of southeastern Ventura County of southern California. It had a moment magnitude of 5.8 and a maximum Mercalli Intensity of VII. This oblique-slip shock resulted in several injuries and $1 million in damage. The epicenter was near the Oxnard Plain and the northern terminus of the Santa Monica Mountains, in the California South Coast region.
The 1979 Saint Elias earthquake occurred near noon local time on 28 February. It measured Mw 7.4–7.6. Though the maximum recorded Modified Mercalli intensity was VII, damage was minimal and there were no casualties due to the remoteness of the faulting. The epicenter lies near the Alaskan border between the United States and Canada.
The 1980 Livermore earthquake occurred on January 24 at 11:00 PST in California. The epicenter of the 5.8 Mw earthquake was a hilly area 12 km (7.5 mi) southeast of Mount Diablo and north of Livermore Valley. The earthquake had a maximum Modified Mercalli intensity of VII. Forty four people were injured and damage across the San Francisco Bay Area totaled $11.5 million, with the majority inflicted at the Lawrence Livermore National Laboratory.
References
- ↑ USGS (September 4, 2009), PAGER-CAT Earthquake Catalog, Version 2008_06.1, United States Geological Survey, archived from the original on 2020-03-13
- ↑ Jackson, F. J.; Molnar, S.; Ghofrani, H.; Atkinson, G. M.; Cassidy, J. F.; Assatourians, K. (2017), "Ground Motions of the December 2015 M4.7 Vancouver Island Earthquake: Attenuation and Site Response", Bulletin of the Seismological Society of America, 107 (6): 2903, Bibcode:2017BuSSA.107.2903J, doi:10.1785/0120170071
- ↑ Stover & Coffman 1993 , pp. 380, 388
- ↑ Stover & Coffman 1993 , pp. 380, 385
- ↑ NGDC 1972
- Sources
- NGDC (1972), Significant Earthquake Database (Data Set), National Geophysical Data Center, NOAA, doi:10.7289/V5TD9V7K
- Stover, C. W.; Coffman, J. L. (1993), Seismicity of the United States, 1568–1989 (Revised), U.S. Geological Survey Professional Paper 1527, United States Government Printing Office
| Authority control databases: National |
|---|
