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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] |
Pacific Standard Time
The Pacific Time Zone (PT) is a time zone encompassing parts of western Canada, the western United States, and western Mexico. Places in this zone observe standard time by subtracting eight hours from Coordinated Universal Time (UTC−08:00). During Daylight saving time in the Americas#Canada, Mexico and the United States, daylight saving time, a time offset of UTC−07:00 is used. In the United States and Canada, this time zone is generically called the Pacific Time Zone. Specifically, time in this zone is referred to as Pacific Standard Time (PST) when standard time is being observed (early November to mid-March), and Pacific Daylight Time (PDT) when daylight saving time (mid-March to early November) is being observed. In Mexico, the corresponding time zone is known as the ''Zona Noroeste'' (Northwest Zone) and observes the same daylight saving schedule as the U.S. and Canada. The largest city in the Pacific Time Zone is Los Angeles, Greater Los Angeles, whose metropolitan ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gulf Of California
The Gulf of California ( es, Golfo de California), also known as the Sea of Cortés (''Mar de Cortés'') or Sea of Cortez, or less commonly as the Vermilion Sea (''Mar Bermejo''), is a marginal sea of the Pacific Ocean that separates the Baja California Peninsula from the Mexico, Mexican mainland. It is bordered by the states of Baja California, Baja California Sur, Sonora, and Sinaloa with a coastline of approximately . Rivers that flow into the Gulf of California include the Colorado River, Colorado, Fuerte River, Fuerte, Mayo River (Mexico), Mayo, Sinaloa River, Sinaloa, Sonora River, Sonora, and the Yaqui River, Yaqui. The surface of the gulf is about . Maximum depths exceed because of the complex geology, linked to plate tectonics. The gulf is thought to be one of the most diverse seas on Earth and is home to more than 5,000 species of micro-invertebrates. Parts of the Gulf of California are a UNESCO World Heritage Site. Geography History The marine expeditions of Fortún ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calexico, California
Calexico () is a city in southern Imperial County, California. Situated on the Mexican border, it is linked economically with the much larger city of Mexicali, the capital of the Mexican state of Baja California. It is about east of San Diego and west of Yuma, Arizona. Calexico, along with six other incorporated Imperial County cities, forms part of the larger populated area known as the Imperial Valley. First explored by Europeans in the 18th century, Calexico began as a small tent community which was ultimately incorporated in 1908. Etymology The name of the city is a portmanteau of California and Mexico. The originally proposed names were ''Santo Tomas'' or ''Thomasville.'' Mexicali is a similarly named city directly across the international border from Calexico, its name being a portmanteau of the words "Mexico" and "California". History The expedition of Spanish explorer Juan Bautista de Anza traveled through the area some time between 1775 and 1776, during Spanish rule ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epicenter
The epicenter, epicentre () or epicentrum in seismology is the point on the Earth's surface directly above a hypocenter or focus, the point where an earthquake or an underground explosion originates. Surface damage Before the instrumental period of earthquake observation, the epicenter was thought to be the location where the greatest damage occurred, but the subsurface fault rupture may be long and spread surface damage across the entire rupture zone. As an example, in the magnitude 7.9 Denali earthquake of 2002 in Alaska, the epicenter was at the western end of the rupture, but the greatest damage was about away at the eastern end. Focal depths of earthquakes occurring in continental crust mostly range from . Continental earthquakes below are rare whereas in subduction zone earthquakes can originate at depths deeper than . Epicentral distance During an earthquake, seismic waves propagate in all directions from the hypocenter. Seismic shadowing occurs on the opposite s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
USCGS Imperial Damage 1940
USCGS may refer to: * U.S. National Geodetic Survey The National Geodetic Survey (NGS) is a United States federal agency that defines and manages a national coordinate system, providing the foundation for transportation and communication; mapping and charting; and a large number of applications ... * UN/LOCODE:USCGS {{dab ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Imperial Valley Press
The Imperial Valley Press (originally known as the ''Imperial Press'') is a daily newspaper printed outside of the Imperial Valley. It was owned by Schurz Communications of South Bend, Indiana South Bend is a city in and the county seat of St. Joseph County, Indiana, St. Joseph County, Indiana, on the St. Joseph River (Lake Michigan), St. Joseph River near its southernmost bend, from which it derives its name. As of the 2020 United S ... from 1965 to 2015. It is owned by Imperial Valley Media; shareholders include Rhode Island Suburban Newspapers. The Imperial Valley Press features local news from all communities of the Imperial Valley and the Mexicali, Baja California area, as well as San Diego County and portions of southwestern Arizona. The newspaper focuses on local news, sports and opinion pieces. Perhaps one of the best-read features of the paper is its "Probe" column, which solicits reader participation and then attempts to answer questions and address other concerns. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1987 Superstition Hills Earthquakes
The 1987 Superstition Hills and Elmore Ranch earthquakes were a pair of earthquakes measuring 6.0 and 6.5 that rattled the Imperial Valley of California. The earthquakes caused damage in Southern California and Mexico, but was limited due to their location in a sparsely populated area. It was felt as far as Las Vegas and Phoenix. More than 90 were injured, and two people were killed in Mexico. Geology The Imperial Valley is a seismically active area in California. It is in this area where the San Andreas Fault and San Jacinto Fault Zone (SJFZ) terminate in the south. This region is a transition zone between the continental transform boundary to oceanic rifting in the Gulf of California. South of the San Andreas Fault and between the Imperial Fault is the Brawley Seismic Zone—the northernmost ridge feature in the Gulf of California ridge–transform boundary. Faults in the Brawley Seismic Zone typically trend northeast, perpendicular to the plate boundary faults. Labeled "cro ... [...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] |
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] |
San Jacinto Fault Zone
The San Jacinto Fault Zone (SJFZ) is a major strike-slip fault zone that runs through San Bernardino, Riverside, San Diego, and Imperial Counties in Southern California. The SJFZ is a component of the larger San Andreas transform system and is considered to be the most seismically active fault zone in the area. Together they relieve the majority of the stress between the Pacific and North American tectonic plates. The SJFZ itself consists of many individual fault segments, some of which have only been individualized as recently as the 1980s, but activity along the line of faults has been documented since the 1890s. One segment of the SJFZ, the Anza seismic gap, has not experienced any major activity since instrumental records have been kept. Each segment was evaluated for its seismic risk and was assigned a probability for the occurrence of a large rupture for the thirty-year period starting in 1995. While several of the large earthquakes along the SJFZ have not resulted in sig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Salton Sea
The Salton Sea is a shallow, landlocked, highly saline body of water in Riverside and Imperial counties at the southern end of the U.S. state of California. It lies on the San Andreas Fault within the Salton Trough that stretches to the Gulf of California in Mexico. Over millions of years, the Colorado River has flowed into the Imperial Valley and deposited alluvium (soil), creating fertile farmland, building up the terrain, and constantly moving its main course and river delta. For thousands of years, the river has alternately flowed into the valley, or diverted around it, creating either a saline lake called Lake Cahuilla, or a dry desert basin, respectively. When the Colorado River flows into the valley, the lake level depends on river flows and the balance between inflow and evaporative loss. When the river diverts around the valley, the lake dries completely, as it did around 1580. Hundreds of archaeological sites have been found in this region, indicating possibly long-ter ... [...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] |
