|
Imperial Fault Zone
The Imperial Fault Zone is a system of geological faults located in Imperial County in the Southern California region, and adjacent Baja California state in Mexico. It cuts across the border between the United States and Mexico. Geology The Imperial Fault Zone is a right lateral-moving strike-slip fault, representing the northernmost transform fault associated with the East Pacific Rise. It is connected to the San Andreas Fault by the Brawley Seismic Zone. It terminates on its southern end at the Cerro Prieto spreading center. The Imperial Fault Zone is thought to accommodate slip from both the San Andreas and the San Jacinto fault zones. However, studies covering the last few hundred years show that the slip rate is insufficient to account for the total slip from the San Andreas system.Treiman, J.Jerome, compiler, 1999, Fault number 132, Imperial fault, in Quaternary fault and fold database of the United States: U.S. Geological Survey website, http://earthquakes.usgs.gov/haz ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
USGS Map Of Imperial Fault Zone
The United States Geological Survey (USGS), formerly simply known as the Geological Survey, is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, and the natural hazards that threaten it. The organization's work spans the disciplines of biology, geography, geology, and hydrology. The USGS is a fact-finding research organization with no regulatory responsibility. The agency was founded on March 3, 1879. The USGS is a bureau of the United States Department of the Interior; it is that department's sole scientific agency. The USGS employs approximately 8,670 people and is headquartered in Reston, Virginia. The USGS also has major offices near Lakewood, Colorado, at the Denver Federal Center, and Menlo Park, California. The current motto of the USGS, in use since August 1997, is "science for a changing world". The agency's previous slogan, adopted on the occasion of its hundredth anniv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Imperial County, California
Imperial County is a county on the southeast border of the U.S. state of California. As of the 2020 census, the population was 179,702, making it the least populous county in Southern California. The county seat is El Centro. Imperial is the most recent California county to be established, as it was created in 1907 out of portions of San Diego County. Imperial County is located in the far southeast of California, in the Imperial Valley. It borders San Diego County to the west, Riverside County to the north, the U.S. state of Arizona to the east and the Mexican state of Baja California to the south. It includes the El Centro Metropolitan Statistical Area and is part of the Southern California border region, the smallest but most economically diverse region in the state. Although this region is a desert, with high temperatures and low average rainfall of per year, the economy is strongly based on agriculture. This is supported by irrigation, with water supplied wholly from th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2010 Baja California Earthquake
The 2010 Baja California earthquake (also known as 2010 Easter earthquake, 2010 Sierra El Mayor earthquake, or 2010 El Mayor – Cucapah earthquake) occurred on April 4 (Easter Sunday) with a moment magnitude of 7.2 and a maximum Mercalli intensity of VII (''Very strong''). The shock originated at (3:40:41 PM PDT) south of Guadalupe Victoria, Baja California, Mexico. The 89-second quake was widely felt throughout northwest Mexico and southern California. It was also the strongest to rock southern California in at least 18 years (since the M 7.3 1992 Landers earthquake), if not longer: the next most recent comparable earthquake—the 1952 Kern County earthquake (M 7.3)—was 58 years earlier. Each of these earthquakes had a similar magnitude, and was also felt across a large swath of North America. Most of the damage occurred in the twin cities of Mexicali and Calexico on the Mexico–United States border. Geology The quake originally was believed to have occurred on the Lagun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1979 Imperial Valley Earthquake
The 1979 Imperial Valley earthquake occurred at 16:16 Pacific Daylight Time (23:16 UTC) on 15 October just south of the Mexico–United States border. It affected Imperial Valley in Southern California and Mexicali Valley in northern Baja California. The earthquake had a relatively shallow hypocenter and caused property damage in the United States estimated at US$30 million. The irrigation systems in the Imperial Valley were badly affected, but no deaths occurred. It was the largest earthquake to occur in the contiguous United States since the 1971 San Fernando earthquake eight years earlier. The earthquake was 6.5 on the scale, with a maximum perceived intensity of IX (''Violent'') on the Mercalli intensity scale. However, most of the intensity measurements were consistent with an overall maximum intensity of VII (''Very strong''), and only the damage to a single structure, the Imperial County Services building in El Centro, was judged to be of intensity IX. Several comprehe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1940 El Centro Earthquake
The 1940 El Centro earthquake (or 1940 Imperial Valley earthquake) occurred at 21:35 Pacific Standard Time on May 18 (05:35 UTC on May 19) 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 to hit the Imperial Valley, and caused widespread damage to irrigation systems and led to the deaths of nine people. Tectonic setting The Salton Trough is part of the complex plate boundary between the Pacific Plate and the North American Plate where it undergoes a transition from the continental transform of the San Andreas Fault s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Richter Magnitude Scale
The Richter scale —also called the Richter magnitude scale, Richter's magnitude scale, and the Gutenberg–Richter scale—is a measure of the strength of earthquakes, developed by Charles Francis Richter and presented in his landmark 1935 paper, where he called it the "magnitude scale". This was later revised and renamed the local magnitude scale, denoted as ML or . Because of various shortcomings of the original scale, most seismological authorities now use other similar scales such as the moment magnitude scale () to report earthquake magnitudes, but much of the news media still erroneously refers to these as "Richter" magnitudes. All magnitude scales retain the logarithmic character of the original and are scaled to have roughly comparable numeric values (typically in the middle of the scale). Due to the variance in earthquakes, it is essential to understand the Richter scale uses logarithms simply to make the measurements manageable (i.e., a magnitude 3 quake factors ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1915 Imperial Valley Earthquakes
The 1915 Imperial Valley earthquakes were two destructive shocks centered near El Centro, California on June 22. The earthquakes measured 6.25 and occurred nearly one hour apart at 19:59 and 20:57 PST. Both shocks were assigned VIII (''Severe'') on the Modified Mercalli intensity scale. Heavy damage occurred in the areas of Mexicali and El Centro, amounting to $900,000. At least six people were killed in the earthquakes. In November, the area was struck by another larger shock, measuring 7.0 centered in Cerro Prieto, Baja California, Mexico. Tectonic setting Brawley Seismic Zone and surrounding area. The red lines are simplified faults. Right-lateral direction of motion of the transform fault is shown (pink arrows). The red rhombs are pull-apart basins; the northern one is the site of the Niland geothermal field, the southern the Cerro Prieto geothermal field. The Salton Trough is an active pull-apart basin forming due to offsets between the numerous strike-slip faults alon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Doublet Earthquake
__NOTOC__ In seismology, doublet earthquakes – and more generally, multiplet earthquakes – were originally identified as multiple earthquakes with nearly identical waveforms originating from the same location. They are now characterized as single earthquakes having two (or more) main shocks of similar magnitude, sometimes occurring within tens of seconds, but sometimes separated by years. The similarity of magnitude – often within 0.4 magnitude – distinguishes multiplet events from aftershocks, which start at about 1.2 magnitude less than the parent shock ( Båth's law) and decrease in magnitude and frequency according to known laws. Doublet/multiplet events also have nearly identical seismic waveforms, as they come from the same rupture zone and stress field, whereas aftershocks, being peripheral to the main rupture, typically reflect more diverse circumstances of origin. Multiplet events overlap in their focal fields (rupture zones), which can be up 100 kilometers acros ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brawley Seismic Zone
The Brawley Seismic Zone (BSZ), also known as the Brawley fault zone, is a predominantly extensional tectonic zone that connects the southern terminus of the San Andreas Fault with the Imperial Fault in Southern California. The BSZ is named for the nearby town of Brawley in Imperial County, California, and the seismicity there is characterized by earthquake swarms. Geology The Brawley Seismic Zone represents the northernmost extension of the spreading center axis associated with the East Pacific Rise which runs up the axis of the Gulf of California and is in the process of rifting the Baja California Peninsula away from the mainland of Mexico, with significant subsidence taking place at southern California's Salton Sea and at Laguna Salada in Baja California. Other major locations along the axis include the Cerro Prieto spreading center located south of Mexicali, and Wagner Basin (a submarine depression in the Gulf of California). The Salton Buttes on the south shore of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
San Andreas Fault
The San Andreas Fault is a continental transform fault that extends roughly through California. It forms the tectonic boundary between the Pacific Plate and the North American Plate, and its motion is right-lateral strike-slip (horizontal). The fault divides into three segments, each with different characteristics and a different degree of earthquake risk. The slip rate along the fault ranges from /yr. It was formed by a transform boundary. The fault was identified in 1895 by Professor Andrew Lawson of UC Berkeley, who discovered the northern zone. It is often described as having been named after San Andreas Lake, a small body of water that was formed in a valley between the two plates. However, according to some of his reports from 1895 and 1908, Lawson actually named it after the surrounding San Andreas Valley. Following the 1906 San Francisco earthquake, Lawson concluded that the fault extended all the way into southern California. In 1953, geologist Thomas Dibblee ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
East Pacific Rise
The East Pacific Rise is a mid-ocean rise (termed an oceanic rise and not a mid-ocean ridge due to its higher rate of spreading that results in less elevation increase and more regular terrain), a divergent tectonic plate boundary located along the floor of the Pacific Ocean. It separates the Pacific Plate to the west from (north to south) the North American Plate, the Rivera Plate, the Cocos Plate, the Nazca Plate, and the Antarctic Plate. It runs south from the Gulf of California in the Salton Sea basin in Southern California to a point near 55° S, 130° W, where it joins the Pacific-Antarctic Ridge trending west-southwest towards Antarctica, near New Zealand (though in some uses the PAR is regarded as the southern section of the EPR). Much of the rise lies about 3200 km (2000 mi) off the South American coast and rises about 1,800–2,700 m (6,000–9,000 ft) above the surrounding seafloor. Overview The oceanic crust is moving away from t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mexico
Mexico (Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatemala, Belize, and the Caribbean Sea; and to the east by the Gulf of Mexico. Mexico covers ,Mexico ''''. . making it the world's 13th-largest country by are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
.jpg "Click for more on -> Imperial County, California")
