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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] |
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] |
Plate Tectonics
Plate tectonics (from the la, label=Late Latin, tectonicus, from the grc, τεκτονικός, lit=pertaining to building) is the generally accepted scientific theory that considers the Earth's lithosphere to comprise a number of large tectonic plates which have been slowly moving since about 3.4 billion years ago. The model builds on the concept of ''continental drift'', an idea developed during the first decades of the 20th century. Plate tectonics came to be generally accepted by geoscientists after seafloor spreading was validated in the mid to late 1960s. Earth's lithosphere, which is the rigid outermost shell of the planet (the crust and upper mantle), is broken into seven or eight major plates (depending on how they are defined) and many minor plates or "platelets". Where the plates meet, their relative motion determines the type of plate boundary: '' convergent'', '' divergent'', or ''transform''. Earthquakes, volcanic activity, mountain-building, and oceanic tr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Masonry
Masonry is the building of structures from individual units, which are often laid in and bound together by mortar; the term ''masonry'' can also refer to the units themselves. The common materials of masonry construction are bricks, building stone such as marble, granite, and limestone, cast stone, concrete blocks, glass blocks, and adobe. Masonry is generally a highly durable form of construction. However, the materials used, the quality of the mortar and workmanship, and the pattern in which the units are assembled can substantially affect the durability of the overall masonry construction. A person who constructs masonry is called a mason or bricklayer. These are both classified as construction trades. Applications Masonry is commonly used for walls and buildings. Brick and concrete block are the most common types of masonry in use in industrialized nations and may be either load-bearing or non-load-bearing. Concrete blocks, especially those with hollow cores, offer va ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
San Diego State University
San Diego State University (SDSU) is a public research university in San Diego, California. Founded in 1897 as San Diego Normal School, it is the third-oldest university and southernmost in the 23-member California State University (CSU) system. In Fall 2022, SDSU hit an all time high enrollment record student body of nearly 37,000 and an alumni base of more than 300,000. It is classified among "R2: Doctoral Universities – High research activity". In the 2015–16 fiscal year, the university obtained $130 million in public and private funding—a total of 707 awards—up from $120.6 million the previous fiscal year. As reported by the Faculty Scholarly Productivity Index released by the Academic Analytics organization of Stony Brook, New York, SDSU had the highest research output of any small research university in the United States in 2006 and 2007. SDSU sponsors the second-highest number of Fulbright Scholars in the State of California, just behind UC Berkeley. Since 2005, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Earthquake Rupture
In seismology, an earthquake rupture is the extent of slip that occurs during an earthquake in the Earth's crust. Earthquakes occur for many reasons that include: landslides, movement of magma in a volcano, the formation of a new fault, or, most commonly of all, a slip on an existing fault. Nucleation A tectonic earthquake begins by an initial rupture at a point on the fault surface, a process known as nucleation. The scale of the nucleation zone is uncertain, with some evidence, such as the rupture dimensions of the smallest earthquakes, suggesting that it is smaller than 100 m while other evidence, such as a slow component revealed by low-frequency spectra of some earthquakes, suggest that it is larger. The possibility that the nucleation involves some sort of preparation process is supported by the observation that about 40% of earthquakes are preceded by foreshocks. However, some large earthquakes, such as the M8.6 1950 India - China earthquake., have no foreshocks and it re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caltech
The California Institute of Technology (branded as Caltech or CIT)The university itself only spells its short form as "Caltech"; the institution considers other spellings such a"Cal Tech" and "CalTech" incorrect. The institute is also occasionally referred to as "CIT", most notably in its alma mater, but this is uncommon. is a private university, private research university in Pasadena, California. Caltech is ranked among the best and most selective academic institutions in the world, and with an enrollment of approximately 2400 students (acceptance rate of only 5.7%), it is one of the world's most selective universities. The university is known for its strength in science and engineering, and is among a small group of Institute of Technology (United States), institutes of technology in the United States which is primarily devoted to the instruction of pure and applied sciences. The institution was founded as a preparatory and vocational school by Amos G. Throop in 1891 and began ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Surface Rupture
In seismology, surface rupture (or ground rupture, or ground displacement) is the visible offset of the ground surface when an earthquake rupture along a fault affects the Earth's surface. Surface rupture is opposed by buried rupture, where there is no displacement at ground level. This is a major risk to any structure that is built across a fault zone that may be active, in addition to any risk from ground shaking. Surface rupture entails vertical or horizontal movement, on either side of a ruptured fault. Surface rupture can affect large areas of land. __TOC__ Lack of surface rupture Not every earthquake results in surface rupture, particularly for smaller and deeper earthquakes. In some cases, however, the lack of surface effects is because the fault that moved does not reach the surface. For example, the 1994 Northridge earthquake had a moment magnitude of 6.7, caused major damage in the Los Angeles area, occurred at below the Earth's surface, but did not cause surface ... [...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] |
Mexicali
Mexicali (; ) is the capital city of the Mexican state of Baja California. The city, seat of the Mexicali Municipality, has a population of 689,775, according to the 2010 census, while the Calexico–Mexicali metropolitan area is home to 1,000,000 inhabitants on both sides of the United States-Mexico border. Mexicali is a regional economic and cultural hub for the border region of The Californias. Mexicali was founded at the turn of the 20th century, when the region's agricultural economy experienced a period of boom. The city rapidly expanded throughout the 20th century, owing to the proliferation of maquiladoras in the city, making the Mexicali economy more interconnected with businesses from across the border. Today, Mexicali is a major manufacturing center and an emerging tourist destination. History The Spaniards arrived in the area after crossing the Sonoran Desert's " Camino del Diablo" or Devil's Road. This led to the evangelization of the area by Catholic missionar ... [...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] |
Imperial, California
Imperial is a city in Imperial County, California, north of El Centro. As of the 2010 census, the city had a population of 14,758. It is part of the El Centro metropolitan area. In 2016, Imperial was the fourth fastest-growing city in the state, gaining 4.1 percent more residents from January 1, 2015, to January 1, 2016. It compares to Imperial County's growth of 1.3 percent and Brawley's growth of 1.2 percent. History Imperial was created by the Imperial Land Company and was named by George Chaffey. Imperial's first post office opened in 1901. Imperial incorporated in 1904. The first mayor of Imperial was Allison Peck. The town-site of Imperial was plotted in 1902 for home and commercial businesses. Its first buildings included a printing press, drug store, grocery store, brick building, and church. The city can also boast of having the first school in the valley and the first Chamber of Commerce. The City of Imperial was incorporated July 12, 1904 thus being the first c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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