1.
Structural basin
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A structural basin is a large-scale structural formation of rock strata formed by tectonic warping of previously flat-lying strata. Structural basins are geological depressions, and are the inverse of domes, some elongated structural basins are also known as synclines. Basins may appear on a map as roughly circular or elliptical. Because the strata dip toward the center, the strata in a basin are progressively younger from the outside in. Basins are often large in extent, often hundreds of kilometers across. Structural basins are important sources of coal, petroleum, and groundwater. The Changing Earth, Exploring Geology and Evolution, 2nd ed. Belmont, Wadsworth Publishing Company,1997
2.
Southern California
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Southern California, often abbreviated as SoCal, is a geographic and cultural region that generally comprises Californias 10 southernmost counties. The region is described as eight counties, based on demographics and economic ties, Imperial, Los Angeles, Orange, Riverside, San Bernardino, San Diego, Santa Barbara. The more extensive 10-county definition, which includes Kern and San Luis Obispo counties, is used and is based on historical political divisions. Southern California is an economic center for the state of California. The 8-county and 10-county definitions are not used for the greater Southern California Megaregion, the megaregions area is more expansive, extending east into Las Vegas, Nevada and south across the Mexican border into Tijuana.5 million people. With over 22 million people, Southern California contains roughly 60 percent of Californias population, located east of Southern California is the Colorado Desert and the Colorado River at the border with Arizona. The Mojave Desert is located at the border with the state of Nevada while towards the south is the Mexico–United States border, within Southern California are two major cities, Los Angeles and San Diego, as well as three of the countrys largest metropolitan areas. With a population of 3,792,621, Los Angeles is the most populous city in California and the second most populous in the United States. South of Los Angeles and with a population of 1,307,402 is San Diego, the second most populous city in the state and the eighth most populous in the nation. The counties of Los Angeles, Orange, San Diego, San Bernardino, and Riverside are the five most populous in the state, the motion picture, television, and music industry are centered in the Los Angeles area in Southern California. Hollywood, a district within Los Angeles, gives its name to the American motion picture industry, headquartered in Southern California are The Walt Disney Company, Sony Pictures, Universal, MGM, Paramount Pictures, 20th Century Fox, and Warner Brothers. Universal, Warner Brothers, and Sony also run major record companies, Southern California is also home to a large homegrown surf and skateboard culture. Companies such as Vans, Volcom, Quiksilver, No Fear, RVCA, some of the worlds biggest action sports events, including the X Games, Boost Mobile Pro, and the U. S. Open of Surfing, are all held in Southern California. Southern California is also important to the world of yachting, the annual Transpacific Yacht Race, or Transpac, from Los Angeles to Hawaii, is one of yachtings premier events. The San Diego Yacht Club held the Americas Cup, the most prestigious prize in yachting, from 1988 to 1995, Southern California is home to many sports franchises and sports networks such as Fox Sports Net. Many locals and tourists frequent the Southern California coast for its popular beaches, the desert city of Palm Springs is popular for its resort feel and nearby open spaces. Southern California is not a geographic designation and definitions of what constitutes Southern California vary. Geographically, Californias North-South midway point lies at exactly 37°958.23 latitude, around 11 miles south of San Jose, however, when the state is divided into two areas, the term Southern California usually refers to the 10 southernmost counties of the state
3.
Peninsular Ranges
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Elevations range from 500 to 10,834 feet. Sierra San Francisco, Sierra de la Giganta, and Sierra de la Laguna in Baja California, Palomar Mountain, home to Palomar Observatory, is in the Peninsular Ranges in San Diego County, as is Viejas Mountain. The Peninsular ranges run predominantly north-south, unlike the Transverse Ranges to their north, rocks in the ranges are dominated by Mesozoic granitic rocks, derived from the same massive batholith which forms the core of the Sierra Nevada Mountains in California. They are part of a province known as the Salinian Block which broke off the North American Plate as the San Andreas Fault. Between this set of ranges and the Transverse Ranges is the complex Malibu Coast—Santa Monica—Hollywood fault, most of the Peninsular Ranges are in the Nearctic ecozone. Several terrestrial ecoregions cover portions of the Peninsular Ranges, on western-coast side of the southern portion of the ranges the Baja California desert ecoregion covers in the southern portion of the Peninsular Ranges in Baja California and Baja California Sur. On eastern side of northern ranges, the Sonoran Desert ecoregion covers southeastern California and northeastern Baja California as far south as the town of Loreto, Baja California Sur. On the eastern side of the Laguna Mountains in San Diego County the Anza-Borrego Desert State Park is known for its profusion of Colorado Desert wildflowers. On eastern-Gulf of California side of the portion of the ranges the Gulf of California xeric scrub ecoregion covers the range in Baja California Sur. The higher portions of the Peninsular Ranges, especially the slopes, are home to coniferous. Cleveland National Forest covers much of the higher Southern California Peninsular Ranges, the vegetation includes oak woodlands and forests of Jeffrey Pine and Coulter Pine. The Sierra Juarez and San Pedro Martir pine-oak forests cover upper slopes of Sierra Juarez and these isolated forests, predominantly Tamarack Pine, Sugar Pine, Parry Pinyon, White Fir, California Incense Cedar, and junipers. Oak species include Coast Live Oak, Engelmann Oak, Canyon Live Oak and these higher portions of the Peninsular Ranges harbor many rare and endemic species. Southern Baja California Sur is part of the Neotropic ecozone and its flora and fauna share many affinities with southern Mexico and Central America. It includes three distinct ecoregions, the Sierra de la Laguna dry forests, Sierra de la Laguna pine-oak forests, Peninsular Ranges index Transverse Ranges List of mountain ranges
4.
Santa Barbara Channel
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The Santa Barbara Channel is a portion of the Pacific Ocean which separates the mainland of California from the northern Channel Islands. It is generally south of the city of Santa Barbara, during the last ice age, the four northern Channel Islands, including Santa Rosa Island, were conjoined into Santa Rosae, a single island that was only five miles off the coast. The Santa Barbara Channel is considered a location, with the islands visible from the mainland on clear days. Excursion boats cross the channel, taking visitors to watch whales, in the perpendicular direction, huge cargo ships and tankers occupy a major shipping lane on their way to or from the ports of Los Angeles and Long Beach. The Channel is the location of oil fields, some of which have substantial reserves. These include the Ellwood, Summerland, Carpinteria offshore and Dos Cuadras fields, some oil exploration and production activities continue in the area, in spite of vigorous opposition from local organizations, such as Santa Barbara-based Get Oil Out. The Santa Barbara Channel contains the worlds largest natural oil seepage - Coal Oil Point, goleta Point is a nearby extension into the channel. Prior to the Holocene era sea levels were lower, such that the water width separating the mainland was much less. This effect had a significant effect upon biological colonization as well as human transport via plank canoes, as examples, the Native American Chumash peoples navigated these waters with ease using their primitive watercraft, allowing communication and trade between island and mainland villages. In terms of biological colonization, C, the most famous endemic species, though now extinct, was the pygmy mammoth, which is often cited as a case study in insular dwarfism. As of at least 2011, a few endangered species of whale have begun to feed in a new area north of the Santa Cruz and Santa Rosa islands of the Santa Barbara Channel. These whales are at risk to be struck by passing through a shipping lane used to move goods south to Los Angeles. About 100 collisions have been documented off of the coast of California since 1982, Oil companies continue efforts for permission to drill in the channel
5.
Oxnard Plain
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The Oxnard Plain is a large coastal plain in southwest Ventura County, California, United States surrounded by the mountains of the Transverse ranges. The 16. 5-mile-long coastline is among the longest stretches of continuous, Ventura County is one of the principal agricultural counties in the state and it is a significant component of the economy with a total annual crop value in the county of over $1.8 billion in 2014. There is strong sentiment for retaining agricultural production, as reflected in the SOAR initiatives that have been approved by voters. This plain has been formed chiefly by the deposition of sediments from Santa Clara River and this plain contained a series of marshes, salt flats, sloughs, and lagoons prior to the expansion of agriculture. The Santa Clara River is one of the largest river systems along the coast of Southern California, there are also several smaller abandoned oil fields. Oil facilities are interspersed with agricultural land uses both east and west of Oxnard, Human settlement at over 5000 B. C. E. has been documented in nearby coastal sites. The presence or absence of water is a predictor of site location in Southern California. Several sites have also documented at Mugu Lagoon. Spanish explorers made sailing expeditions along the coast of southern California between the mid-1500s and mid-1700s, in the 18th century, Spain began the colonization and inland exploration of Alta California. They established a system consisting of missions, presidios. Mission San Buenaventura was founded in 1782 next to the Ventura River,10 miles upcoast from the Santa Clara River, the Oxnard plain was used for grazing herds of livestock which required thousands of acres. The traditional way of life of the Chumash people became increasingly unstable and unsustainable on the Oxnard Plain with the introduction of these animals. The destruction wrought by the livestock and shortages of wild plants that used for food may have made the missions appear to be the only viable alternative to a disintegrating way of life. At its peak in 1816, the mission had over 41,000 animals including 23,400 cattle,12,144 sheep, the 4,493 horses constituted one of the largest stables of horses of the California mission sites. The severe decrease in the Chumash population was in response to a set of social, economic. Mexico gained its independence from Spain in 1822, with the secularization of the missions by the Mexican government in June 1836, their lands were granted as rewards for loyal service or in response to petitions by individuals. Most of the land was divided up into large ranchos by 1846. This opened up the Oxnard Plain to further settlement by Europeans, control of the area was transferred to the United States under the Treaty of Guadalupe Hidalgo in 1848 and California became the 31st state in the Union in 1850
6.
San Fernando Valley
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The San Fernando Valley is an urbanized valley located in Los Angeles County, California, defined by the mountains of the Transverse Ranges circling it. Home to 1.8 million people, it lies north of the larger, nearly two thirds of the valleys land area is part of the city of Los Angeles. The other incorporated cities in the valley are Glendale, Burbank, San Fernando, Hidden Hills, the Los Angeles River begins at the confluence of Calabasas Creek and Bell Creek, between Canoga Park High School and Owensmouth Ave. in Canoga Park. These creeks headwaters are in the Santa Monica Calabasas foothills, the Simi Hills Hidden Hills, Santa Susana Field Laboratory, the river flows eastward along the southern regions of the Valley. One of the rivers two unpaved sections can be found at the Sepulveda Basin, a seasonal river, the Tujunga Wash, drains much of the western facing San Gabriel Mountains and passes into and then through the Hansen Dam Recreation Center in Lake View Terrace. It flows south along the Verdugo Mountains through the communities of the valley to join the Los Angeles River in Studio City. Other notable tributaries of the river include Dayton Creek, Caballero Creek, Bull Creek, Pacoima Wash, the elevation of the floor of the valley varies from about 600 ft to 1,200 ft above sea level. Universal City, an enclave in the part of the valley, is unincorporated land housing the Universal Studios filming lot. Mulholland Drive, which runs along the ridgeline of the Santa Monica Mountains, in this Mediterranean climate, post-1790s European agriculture for the missions support consisted of grapes, figs, olives, and general garden crops. The San Fernando Valley contains five incorporated cities—Glendale, Burbank, San Fernando, Hidden Hills and Calabasas—and part of a sixth, Los Angeles, the unincorporated communities are governed by the County of Los Angeles. The Los Angeles city section of the valley is divided into seven city districts,2,3,4,5,6,7 and 12. Of the 95 neighborhood councils in the city,34 are in the valley, the valley is represented in the California State Legislature by seven members of the State Assembly and five members of the State Senate. The valley is divided into five congressional districts, the San Fernando Valley, for the most part, tends to support Democrats in state and national elections. This is especially true in the areas which include Sherman Oaks. The Los Angeles satellite administrative center for the valley, The Civic Center Van Nuys, is in Van Nuys. The area in and around the Van Nuys branch of Los Angeles City Hall is home to a station, municipal and superior courts. Northridge is home to California State University, Northridge, many branches of the Los Angeles Public Library are located in the valley. For independent libraries see Incorporated Cities in the Municipalities and districts list below, Los Angeles Police Department, Los Angeles County Sheriffs Department, and independent valley city departments
7.
San Gabriel Valley
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The San Gabriel Valley is one of the principal valleys of Southern California, lying generally to the east of the city of Los Angeles. At one time predominantly agricultural, the San Gabriel Valley is today almost entirely urbanized and is an part of the Greater Los Angeles metropolitan area. It is one of the most ethnically diverse regions in the country, about 200 square miles in size, the valley includes thirty-one cities and five unincorporated communities. In 1886, Pasadena was the first independent incorporated city located in Los Angeles County. The San Gabriel Valley is in Los Angeles County, some of Whittier sits below the Puente Hills. Although these hills are small compared to the San Gabriel Mountains and this is similar to Montebello, which is a member of the Gateway Cities Council of Governments, despite geographically being part of the San Gabriel Valley. The 57 Freeway is generally considered the line between the Pomona and San Gabriel valleys. However, for statistical and economic development purposes, the County of Los Angeles generally includes these six cities as part of the San Gabriel Valley, the community of El Sereno, in the city of Los Angeles, is situated at the westernmost edge of the Valley. Unofficial estimates place the population of the San Gabriel Valley at around 2 million—roughly a fifth of the population of Los Angeles County. Before the arrival of the Spaniards, the land along the Rio Hondo River, the Tongva occupied much of the Los Angeles basin and the islands of Santa Catalina, San Nicolas, San Clemente and Santa Barbara. In 1542, when the Portuguese explorer João Rodrigues Cabrilho arrived off the shores of San Pedro, the Tongva were the people who rowed the remarkable Tiats out to meet Cabrilho. The language of the Tongva was different from the neighboring Indian tribes, the Tongva also provide the origin of many current names, Piwongna – Pomona, Pasakeg-na – Pasadena, Cucomog-na – Cucamonga. The Gabrielinos lived in structures with thatched exteriors. Both sexes wore long hair styles and tattooed their bodies, during warm weather the men wore little clothing, but the women would wear minimal skirts made of animal hides. During the cold weather they would wear animal skin capes, European diseases killed many of the Tongva and by 1870 the area had few remaining native inhabitants. Today, several bands of Tongva people live in the Los Angeles area, on July 30, the expedition crossed the San Gabriel River and continued north toward what is now the city of Los Angeles. To cross the river, the built an rough bridge, which gave the name La Puente to todays San Gabriel Valley city. A few years later, a mission was established near the river crossing, Mission San Gabriel Arcangel was founded by Franciscan Father Junipero Serra, first head of the Spanish missions in California, on September 8,1771
8.
Drainage basin
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A drainage basin or catchment area is any area of land where precipitation collects and drains off into a common outlet, such as into a river, bay, or other body of water. Drainage basins connect into other drainage basins at elevations in a hierarchical pattern, with smaller sub-drainage basins. Other terms used to describe drainage basins are catchment, catchment basin, drainage area, river basin and water basin. In closed drainage basins the water converges to a point inside the basin, known as a sink, which may be a permanent lake. The drainage basin acts as a funnel by collecting all the water within the covered by the basin. Each drainage basin is separated topographically from adjacent basins by a perimeter, drainage basins are similar but not identical to hydrologic units, which are drainage areas delineated so as to nest into a multi-level hierarchical drainage system. Hydrologic units are defined to allow multiple inlets, outlets, or sinks, in a strict sense, all drainage basins are hydrologic units but not all hydrologic units are drainage basins. Drainage basins of the oceans and seas of the world. Grey areas are endorheic basins that do not drain to the oceans, the following is a list of the major ocean basins, About 48. 7% of the worlds land drains to the Atlantic Ocean. The two major mediterranean seas of the world also flow to the Atlantic, The Caribbean Sea and Gulf of Mexico basin includes most of the U. S. The Mediterranean Sea basin includes much of North Africa, east-central Africa, Southern, Central, and Eastern Europe, Turkey, and the areas of Israel, Lebanon. Just over 13% of the land in the world drains to the Pacific Ocean, the Indian Oceans drainage basin also comprises about 13% of Earths land. It drains the eastern coast of Africa, the coasts of the Red Sea and the Persian Gulf, the Indian subcontinent, Burma, antarctica comprises approximately eight percent of the Earths land. The five largest river basins, from largest to smallest, are the basins of the Amazon, the Río de la Plata, the Congo, the Nile, and the Mississippi. The three rivers that drain the most water, from most to least, are the Amazon, Ganga, endorheic drainage basins are inland basins that do not drain to an ocean. Around 18% of all land drains to endorheic lakes or seas or sinks, the largest of these consists of much of the interior of Asia, which drains into the Caspian Sea, the Aral Sea, and numerous smaller lakes. Some of these, such as the Great Basin, are not single drainage basins but collections of separate, in endorheic bodies of standing water where evaporation is the primary means of water loss, the water is typically more saline than the oceans. An extreme example of this is the Dead Sea, drainage basins have been historically important for determining territorial boundaries, particularly in regions where trade by water has been important
9.
Santa Monica Mountains
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The Santa Monica Mountains is a coastal mountain range in Southern California, paralleling the Pacific Ocean. It is part of the Transverse Ranges, because of its proximity to densely populated regions, it is one of the most visited natural areas in California. Santa Monica Mountains National Recreation Area is located in this mountain range, the range extends approximately 40 miles east-west from the Hollywood Hills in Los Angeles to Point Mugu in Ventura County. The mountain range contributed to the isolation of this vast coastal plain before regular transportation routes reached western Ventura County, the eastern mountains form a barrier between the San Fernando Valley and the Los Angeles Basin, separating the Valley on the north and west-central Los Angeles on the south. The Santa Monica Mountains are parallel to Santa Susana Mountains, which are located north of the mountains across the San Fernando Valley. The range is of height, with no particularly craggy or prominent peaks outside the Sandstone Peak. While often rugged and wild, the hosts a substantial amount of human activity. Houses, roads, businesses, and recreational centers are dotted throughout the Santa Monica Mountains, a number of creeks in the Santa Monica Mountains are part of the Los Angeles River watershed. Beginning at the end of the San Fernando Valley the river runs to the north of the mountains. After passing between the range and the Verdugo Mountains it flows south around Elysian Park defining the easternmost extent of the mountains, the Santa Monica Mountains have more than 1,000 archeology sites of significance, primarily from the Californian Native American cultures of the Tongva and Chumash people. The mountains were part of their homelands for over eight thousand years before the arrival of the Spanish. The Spanish mission system had a impact on their culture and by 1831. Geologists consider the northern Channel Islands to be an extension of the Santa Monicas into the Pacific Ocean. The range was created by repeated episodes of uplifting and submergence by the Raymond Fault that created complex layers of sedimentary rock, volcanic intrusions have been exposed, including the poorly named, andesitic, Sandstone Peak the highest in the range at 3,111 feet. Malibu Creek, which eroded its own channel while the mountains were slowly uplifted, the Santa Monica Mountains have dry summers with frequent coastal fog on the ocean side of the range and wet, cooler winters. In the summer, the climate is dry, which makes the range prone to wildfires. Snow is unusual in the Santa Monica Mountains, since they are not as high as the nearby San Gabriel Mountains. The highest slopes of the central and western Santa Monica Mountains average as much as 27 inches of rain per year, the bulk of the rain falls between November and March
10.
Subsidence
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Subsidence is the motion of a surface as it shifts downward relative to a datum such as sea level. The opposite of subsidence is uplift, which results in an increase in elevation, ground subsidence is of concern to geologists, geotechnical engineers and surveyors. Subsidence frequently causes problems in karst terrains, where dissolution of limestone by fluid flow in the subsurface causes the creation of voids. If the roof of these voids becomes too weak, it can collapse and this type of subsidence can result in sinkholes which can be many hundreds of meters deep. Several types of mining, and specifically methods which intentionally cause the extracted void to collapse will result in surface subsidence. Mining-induced subsidence is relatively predictable in its magnitude, manifestation and extent, mining-induced subsidence is nearly always very localized to the surface above the mined area, plus a margin around the outside. Where mining activity is planned, mining-induced subsidence can be successfully managed if there is co-operation from all of the stakeholders and this is accomplished through a combination of careful mine planning, the taking of preventive measures, and the carrying out of repairs post-mining. If natural gas is extracted from a gas field the initial pressure in the field will drop over the years. The gas pressure also supports the soil layers above the field, if the pressure drops, the soil pressure increases and this leads to subsidence at the ground level. Since exploitation of the Slochteren gas field started in the late 1960s the ground level over a 250 km² area has dropped by a current maximum of 30 cm, the Geospatial Information Authority of Japan reported immediate subsidence caused by the 2011 Tōhoku earthquake. In Northern Japan, subsidence of 0.50 m was observed on the coast of the Pacific Ocean in Miyako, Tōhoku, while Rikuzentakata, in the south at Sōma, Fukushima,0.29 m was observed. The maximum amount of subsidence was 1.2 m, coupled with horizontal diastrophism of up to 5.3 m on the Oshika Peninsula in Miyagi Prefecture, the habitation of lowlands, such as coastal or delta plains, requires drainage. The resulting aeration of the leads to the oxidation of its organic components, such as peat. This applies especially when water levels are periodically adapted to subsidence, in order to maintain desired unsaturated zone depths. In addition to this, drained soils consolidate as a result of increased effective stress, in this way, land subsidence has the potential of becoming self-perpetuating, having rates up to 5 cm/yr. Water management used to be tuned primarily to such as crop optimisation but, to varying extents. When differential stresses exist in the Earth, these can be accommodated either by geological faulting in the brittle crust, or by flow in the hotter. Where faults occur, absolute subsidence may occur in the wall of normal faults
11.
Turonian
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The Turonian is, in the ICS geologic timescale, the second age in the Late Cretaceous epoch, or a stage in the Upper Cretaceous series. It spans the time between 93.9 ±0.8 Ma and 89.8 ±1 Ma, the Turonian is preceded by the Cenomanian stage and underlies the Coniacian stage. At the beginning of the Turonian an anoxic event took place which is called the Cenomanian-Turonian boundary event or the Bonarelli Event, the Turonian was defined by the French paleontologist Alcide dOrbigny in 1842. Orbigny named it after the French city of Tours in the region of Touraine, the base of the Turonian stage is defined as the place where the ammonite species Wutinoceras devonense first appears in the stratigraphic column. The official reference profile for the base of the Turonian is located in the Rock Canyon anticline near Pueblo, the top of the Turonian stage is defined as the place in the stratigraphic column where the inoceramid bivalve species Cremnoceramus rotundatus first appears. The Turonian is sometimes subdivided in Lower/Early, Middle and Upper/Late substages or subages, inoceramids are bivalve Mollusca related to todays mussels. & Smith, A. G.2004, A Geologic Time Scale 2004, & Cobban, W. A.2005, The Global Boundary Stratotype Section and Point for the base of the Turonian Stage of the Cretaceous, Pueblo, Colorado, U. S. A
12.
Transtension
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Transtension is the state in which a rock mass or area of the Earths crust experiences both extensive and transtensive shear. As such, transtensional regions are characterised by both extensional structures and wrench structures, in general, many tectonic regimes that were previously defined as simple strike-slip shear zones are actually transtensional. It is unlikely that a body will experience pure extension or pure strike-slip. Transtensional shear zones are characterized by the co-existence of different structures, end member structures include pure strike-slip faults and purely extensional dip-slip faults. Faults which have components of both are abundant, releasing bends are transtensional structures that form where the orientation of a strike-slip fault becomes oblique to the regional slip vector causing local extension. They also form where two segments of a strike-slip fault overlap, and the zone between the segments experiences transtension. Releasing bends often form negative flower structures or pull-apart basins, dead Sea Salton Sea Sea of Marmara on the North Anatolian Fault Vienna Basin Rift Strike-slip tectonics Structural geology Transpression
13.
Isostasy
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Isostasy is the state of gravitational equilibrium between Earths crust and mantle such that the crust floats at an elevation that depends on its thickness and density. This concept is invoked to explain how different topographic heights can exist at Earths surface, when a certain area of Earths crust reaches the state of isostasy, it is said to be in isostatic equilibrium. Isostasy does not upset equilibrium but instead restores it and it is generally accepted that Earth is a dynamic system that responds to loads in many different ways. However, isostasy provides an important view of the processes that are happening in areas that are experiencing vertical movement. In the simplest example, isostasy is the principle of buoyancy wherein an object immersed in a fluid is buoyed with a equal to the weight of the displaced fluid. The general term isostasy was coined in the year 1889 by the American geologist Clarence Dutton, the Vening Meinesz, or flexural isostasy model – where the lithosphere acts as an elastic plate and its inherent rigidity distributes local topographic loads over a broad region by bending. Airy and Pratt isostasy are statements of buoyancy, whereas flexural isostasy is a statement of buoyancy when deflecting a sheet of finite elastic strength. The basis of the model is Pascals law, and particularly its consequence that, within a fluid in static equilibrium, in other words, h1⋅ρ1 = h2⋅ρ2 = h3⋅ρ3 =. This hypothesis was suggested to explain how large topographic loads such as seamounts could be compensated by regional rather than local displacement of the lithosphere. When large amounts of sediment are deposited on a particular region, similarly, when large amounts of material are eroded away from a region, the land may rise to compensate. Therefore, as a range is eroded, the range rebounds upwards to be eroded further. An analogy may be made with an iceberg—it always floats with a proportion of its mass below the surface of the water. If more ice is added to the top of the iceberg, if a layer of ice is somehow sliced off the top of the iceberg, the remaining iceberg will rise. Similarly, Earths lithosphere floats in the asthenosphere, when continents collide, the continental crust may thicken at their edges in the collision. If this happens, much of the thickened crust may move downwards rather than up as with the iceberg analogy, the idea of continental collisions building mountains up is therefore rather a simplification. Instead, the crust thickens and the part of the thickened crust may become a mountain range. However, some continental collisions are far more complex than this, the formation of ice sheets can cause Earths surface to sink. Conversely, isostatic rebound is observed in areas once covered by ice sheets that have now melted, such as around the Baltic Sea
14.
San Andreas Fault
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The San Andreas Fault is a continental transform fault that extends roughly 800 miles through California. It forms the boundary between the Pacific Plate and the North American Plate, and its motion is right-lateral strike-slip. The fault was first identified in 1895 by Professor Andrew Lawson of UC Berkeley and 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, following the 1906 San Francisco earthquake, Lawson concluded that the fault extended all the way into southern California. In 1953, geologist Thomas Dibblee astounded the scientific establishment with his conclusion that hundreds of miles of lateral movement could occur along the fault. A project called the San Andreas Fault Observatory at Depth near Parkfield, Monterey County, is drilling into the fault to improve prediction and this is the approximate location of the epicenter of the 1906 San Francisco earthquake. The fault returns onshore at Bolinas Lagoon just north of Stinson Beach in Marin County, from Fort Ross the northern segment continues overland, forming in part a linear valley through which the Gualala River flows. It goes back offshore at Point Arena, after that, it runs underwater along the coast until it nears Cape Mendocino, where it begins to bend to the west, terminating at the Mendocino Triple Junction. The central segment of the San Andreas fault runs in a direction from Parkfield to Hollister. The southern segment begins near Bombay Beach, California, box Canyon, near the Salton Sea, contains upturned strata associated with that section of the fault. The fault then runs along the base of the San Bernardino Mountains, crosses through the Cajon Pass. These mountains are a result of movement along the San Andreas Fault and are called the Transverse Range. In Palmdale, a portion of the fault is easily examined at a roadcut for the Antelope Valley Freeway, the fault continues northwest alongside the Elizabeth Lake Road to the town of Elizabeth Lake. As it passes the towns of Gorman, Tejon Pass and Frazier Park and this restraining bend is thought to be where the fault locks up in Southern California, with an earthquake-recurrence interval of roughly 140–160 years. Northwest of Frazier Park, the runs through the Carrizo Plain. The Elkhorn Scarp defines the fault trace along much of its length within the plain, the southern segment, which stretches from Parkfield in Monterey County all the way to the Salton Sea, is capable of an 8. 1-magnitude earthquake. At its closest, this fault passes about 35 miles to the northeast of Los Angeles. Such a large earthquake on this segment would kill thousands of people in Los Angeles, San Bernardino, Riverside, and surrounding areas
15.
Strike-slip
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In geology, a fault is a planar fracture or discontinuity in a volume of rock, across which there has been significant displacement as a result of rock-mass movement. Large faults within the Earths crust result from the action of tectonic forces. Energy release associated with movement on active faults is the cause of most earthquakes. A fault plane is the plane that represents the surface of a fault. A fault trace or fault line is the intersection of a plane with the ground surface. A fault trace is also the line commonly plotted on maps to represent a fault. Since faults do not usually consist of a single, clean fracture, the two sides of a non-vertical fault are known as the hanging wall and footwall. By definition, the wall occurs above the fault plane. This terminology comes from mining, when working a tabular ore body, because of friction and the rigidity of rocks, they cannot glide or flow past each other easily, and occasionally all movement stops. A fault in ductile rocks can also release instantaneously when the rate is too great. The energy released by instantaneous strain-release causes earthquakes, a common phenomenon along transform boundaries, slip is defined as the relative movement of geological features present on either side of a fault plane, and is a displacement vector. A faults sense of slip is defined as the motion of the rock on each side of the fault with respect to the other side. In practice, it is only possible to find the slip direction of faults. Based on direction of slip, faults can be categorized as, strike-slip. Dip-slip, offset is predominantly vertical and/or perpendicular to the fault trace, oblique-slip, combining significant strike and dip slip. The fault surface is usually vertical and the footwall moves either left or right or laterally with very little vertical motion. Strike-slip faults with left-lateral motion are known as sinistral faults. Those with right-lateral motion are known as dextral faults
16.
Anticline
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In structural geology, an anticline is a type of fold that is an arch-like shape and has its oldest beds at its core. A typical anticline is convex up in which the hinge or crest is the location where the curvature is greatest, anticlines can be recognized and differentiated from antiforms by a sequence of rock layers that become progressively older toward the center of the fold. Therefore, if age relationships between various rock strata are unknown, the term antiform should be used, the progressing age of the rock strata towards the core and uplifted center, are the trademark indications for evidence of anticlines on a geologic map. These formations occur because anticlinal ridges typically develop above thrust faults during crustal deformations, the uplifted core of the fold causes compression of strata that preferentially erodes to a deeper stratigraphic level relative to the topographically lower flanks. Motion along the fault including both shortening and extension of tectonic plates, usually also deforms strata near the fault and this can result in an asymmetrical or overturned fold. An antiform can be used to describe any fold that is convex up and it is the relative ages of the rock strata that separate anticlines from antiforms. The hinge of an anticline refers to the location where the curvature is greatest, the hinge is also the highest point on a stratum along the top of the fold. The culmination also refers to the highest point along any geologic structure, the limbs are the sides of the fold that display less curvature. The inflection point is the area on the limbs where the curvature changes direction, the axial surface is an imaginary plane connecting the hinge of each layer of rock stratum through the cross section of an anticline. If the axial surface is vertical and the angles on each side of the fold are equivalent, if the axial plane is tilted or offset then the anticline is asymmetrical. An anticline that is cylindrical has a well-defined axial surface, whereas non-cylindrical anticlines are too complex to have an axial plane. If the angle between the limbs is large, then the fold is a fold, but if the angle between the limbs is small, then the fold is a tight fold. If an anticline plunges, it will form Vs on a map view that point in the direction of plunge. A plunging anticline has a hinge that is not parallel to the earths surface, all anticlines and synclines have some degree of plunge. Periclinal folds are a type of anticlines that have a well-defined, folds in which the limbs dip toward the hinge and display a more U-like shape are called synclines. They usually flank the sides of anticlines and display opposite characteristics, a synclines oldest rock strata are in its outer limbs, the rocks become progressively younger toward its hinge. A monocline is a bend in the resulting in a local steepening in only one direction of dip. Monoclines have the shape of a carpet draped over a stairstep, an anticline that has been more deeply eroded in the center is called a breached or scalped anticline
17.
Isopach map
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An isopach map illustrates thickness variations within a tabular unit, layer or stratum. Isopachs are contour lines of equal thickness over an area, Isopach maps are utilized in hydrographic survey, stratigraphy, sedimentology, structural geology, petroleum geology and volcanology. An isopach map is similar to a map, but these terms actually describe different methods of displaying thickness variations within a layer. An isopach map displays lines of equal thickness in a layer where the thicknesses are measured perpendicular to the layer boundaries, Isopach maps in geology are also referred to as True Stratigraphic Thickness maps. An isochore map displays lines of equal thickness in a layer where the thicknesses are measured vertically, isochore maps in geology are also referred to as True Vertical Thickness maps. Thus, an isochore and isopach map are the same only when both the top and bottom surfaces of the layer shown are horizontal. When the layer shown is inclined, as is usually the case, unfortunately the terms isopach and isochore are widely confused, and many times maps of True Vertical Thickness, which by definition are isochore maps, are incorrectly labeled isopach maps. Geology of Petroleum, W. H. Freeman and Company, San Francisco,724 p. Tearpock, Daniel J. and Bischke, applied Subsurface Geological Mapping with Structural Methods, Prentice- Hall, Englewood Cliffs 822 p. Oilfield Glossary Isopach maps vs isochore maps
18.
La Brea Tar Pits
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The La Brea Tar Pits are a group of tar pits around which Hancock Park was formed in urban Los Angeles. Natural asphalt has seeped up from the ground in this area for tens of thousands of years, the tar is often covered with dust, leaves, or water. Over many centuries, the bones of animals that were trapped in the tar were preserved, Page Museum is dedicated to researching the tar pits and displaying specimens from the animals that died there. The La Brea Tar Pits is a registered National Natural Landmark, the modern name is an example of a tautological place name, the La Brea Tar Pits literally means the the tar tar pits. The tar pits visible today are actually from human excavation, the lake pit was originally an asphalt mine. The other pits visible today were produced between 1913 and 1915, when over 100 pits were excavated in search of large mammal bones, various combinations of asphaltum and waggler have since filled in these holes. Normally, the asphalt appears in vents, hardening as it oozes out and these can be seen in several areas of the park. Tar pits are composed of heavy oil fractions called gilsonite, which seeped from the Earth as oil, in Hancock Park, crude oil seeps up along the 6th Street Fault from the Salt Lake Oil Field, which underlies much of the Fairfax District north of the park. The oil reaches the surface and forms pools at several locations in the park and this seepage has been happening for tens of thousands of years. From time to time, the asphalt would form a thick enough to trap animals. Animals would wander in, become trapped, and eventually die, predators would enter to eat the trapped animals and also become stuck. As the bones of dead animals sink into the asphalt, it soaks into them, lighter fractions of petroleum evaporate from the asphalt, leaving a more solid substance, which encases the bones. Examples of some of these are on display in the George C, radiometric dating of preserved wood and bones has given an age of 38,000 years for the oldest known material from the La Brea seeps. The pits still ensnare organisms today, so most of the pits are fenced to protect humans, the Native American Chumash and Tongva people living in the area built boats unlike any others in North America prior to contact by settlers. This innovative form of transportation allowed access up and down the coastline, the Portolá expedition, a group of Spanish explorers led by Gaspar de Portolá, made the first written record of the tar pits in 1769. The scouts reported that they had come across many of these springs and had seen large swamps of them, enough, they said, to caulk many vessels. We were not so lucky ourselves as to see these tar geysers, much though we wished it, as it was some distance out of the way we were to take and we christened them Los Volcanes de Brea. The original Rancho La Brea land grant stipulated that the tar pits be open to the public for the use of the local Pueblo, initially, they mistook the bones in the pits for the remains of pronghorn antelope or cattle that had become mired
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Oil sands
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Oil sands, or more technically bituminous sands, are a type of unconventional petroleum deposit. Natural bitumen deposits are reported in countries, but in particular are found in extremely large quantities in Canada. Other large reserves are located in Kazakhstan, Russia, and Venezuela, the estimated worldwide deposits of oil are more than 2 trillion barrels, the estimates include deposits that have not been discovered. Proven reserves of bitumen contain approximately 100 billion barrels, and total natural bitumen reserves are estimated at 249.67 Gbbl worldwide, of which 176.8 Gbbl, or 70. 8%, are in Alberta, Canada. Oil sands reserves have only recently been considered to be part of the oil reserves, as higher oil prices and new technology enable profitable extraction. Oil produced from bitumen sands is often referred to as oil or crude bitumen. Crude bitumen is a thick, sticky form of oil, so heavy. At room temperature, it is much like cold molasses, the World Energy Council defines natural bitumen as oil having a viscosity greater than 10,000 centipoise under reservoir conditions and an API gravity of less than 10° API. The Orinoco Belt in Venezuela is sometimes described as oil sands, Natural bitumen and extra-heavy oil differ in the degree by which they have been degraded from the original conventional oils by bacteria. According to the WEC, extra-heavy oil has a gravity of less than 10° API, according to the study ordered by the Government of Alberta and conducted by Jacobs Engineering Group, emissions from oil-sand crude are 12% higher than from conventional oil. The exploitation of bituminous deposits and seeps dates back to Paleolithic times, the earliest known use of bitumen was by Neanderthals, some 40,000 years ago. Bitumen has been found adhering to stone tools used by Neanderthals at sites in Syria, after the arrival of Homo sapiens, humans used bitumen for construction of buildings and waterproofing of reed boats, among other uses. In ancient Egypt, the use of bitumen was important in preparing Egyptian mummies, in ancient times, bitumen was primarily a Mesopotamian commodity used by the Sumerians and Babylonians, although it was also found in the Levant and Persia. The area along the Tigris and Euphrates rivers was littered with hundreds of pure bitumen seepages, the Mesopotamians used the bitumen for waterproofing boats and buildings. In Europe, they were mined near the French city of Pechelbronn. The name tar sands was applied to bituminous sands in the late 19th, since then, coal gas has almost completely been replaced by natural gas as a fuel, and coal tar as a material for paving roads has been replaced by the petroleum product asphalt. Oil sands are now an alternative to conventional crude oil, in Canada, the First Nation peoples had used bitumen from seeps along the Athabasca and Clearwater Rivers to waterproof their birch bark canoes from early prehistoric times. The Canadian oil sands first became known to Europeans in 1719 when a Cree native named Wa-Pa-Su brought a sample to Hudsons Bay Company fur trader Henry Kelsey, who commented on it in his journals
20.
Dodger Stadium
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Opened 55 years ago on April 10,1962, it was constructed in less than three years at a cost of $23 million, financed by private sources. Often referred to as a ballpark, the stadium has seen 12 no-hitters. The stadium hosted the Major League Baseball All-Star Game in 1980 and it also hosted the semifinals and finals of the 2009 and 2017 World Baseball Classics. It also hosted exhibition baseball during the 1984 Summer Olympics, the stadium hosted a soccer tournament on August 3,2013 featuring four clubs, the hometown team Los Angeles Galaxy, and European giants Real Madrid, Everton, and Juventus. For the first time at Dodger Stadium, the Los Angeles Kings, the land for Dodger Stadium was purchased from local owners and inhabitants in the early 1950s by the city of Los Angeles using eminent domain with funds from the Federal Housing Act of 1949. Before construction could begin on the project, the local political climate changed greatly when Norris Poulson was elected mayor of Los Angeles in 1953. Proposed public housing such as Elysian Park Heights lost most of their support as they became associated with socialist ideals. It was not until June 3,1958, when Los Angeles voters approved a Taxpayers Committee for Yes on Baseball referendum, Los Angeles-based Mike Davis, in his seminal work on the city, City of Quartz, describes the process of gradually convincing Chavez Ravine homeowners to sell. With nearly all of the original Spanish-speaking homeowners initially unwilling to sell, developers resorted to offering immediate cash payments, ground was broken for Dodger Stadium on September 17,1959. The top of local ridges were removed and the soil was used to fill in Sulfur and Cemetery Ravines to provide a surface for a parking lot. A local elementary school was simply buried and sits beneath the parking lot northwest of third base, a total of 8 million cubic yards of earth were moved in the process of building the stadium. 21,000 precast concrete units, some weighing as much as 32 tons, were fabricated onsite, the stadium was originally designed to be expandable to 85,000 seats by expanding the upper decks over the outfield pavilions, the Dodgers have never pursued such a project. Dodger Stadium was also the home of the Los Angeles Angels from 1962 through 1965, to avoid constantly referring to their landlords, the Angels called the park Chavez Ravine Stadium, after the geographic feature in which the stadium sits. At the conclusion of the 2005 season, the Los Angeles Dodgers made major renovations during the subsequent off-season, the largest of these improvements was the replacement of nearly all the seats in the stadium. The seats that were removed had been in use since 1975 and helped give the stadium its unique space age feel with a palette of bright yellow, orange, blue. The new seats are in the original 1962 color scheme consisting of yellow, light orange, turquoise,2,000 pairs of seats were made available for purchase at $250, with the proceeds going to charity. The baseline seating sections have been converted into retro-style box seating, adding leg room, other repairs were made to the concrete structure of the stadium. These improvements mark the second phase of an improvement plan for Dodger Stadium
21.
Los Angeles City Oil Field
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The Los Angeles City Oil Field is a large oil field north of Downtown Los Angeles. Long and narrow, it extends from south of Dodger Stadium west to Vermont Avenue. Its former productive area amounts to 780 acres, discovered in 1890, and made famous by Edward Dohenys successful well in 1892, the field was once the top producing oil field in California, accounting for more than half of the states oil in 1895. In its peak year of 1901, approximately 200 separate oil companies were active on the field, which is now entirely built over by dense residential and commercial development. As of 2011 only one oil well remains active – behind a fence on South Mountain View Avenue one block east of Alvarado Street in the Westlake neighborhood, producing about 3.5 barrels per day. The fortunes made during development of the field led directly to the discovery, of the 1,250 wells once drilled on the field, and the forest of derricks that once covered the low hills north of Los Angeles from Elysian Park west, little above-ground trace remains. The Los Angeles City field is one of many in the Los Angeles Basin, to the west are the still-productive Salt Lake and Beverly Hills fields, to the south is the Los Angeles Downtown Oil Field. Ten miles east-southeast is the Brea-Olinda field, the first to be worked in the region, even larger fields are still productive in other parts of the basin, such as the giant Wilmington field which stretches from Carson to Long Beach. Terrain in the vicinity of the Los Angeles City field includes gently rolling hills cut by ravines draining south, elevations range from around 250 to 500 feet above sea level, with the highest elevations in Elysian Park near Dodger Stadium. Urban development is dense in the part of Los Angeles containing the fields productive area, with numerous apartment blocks mixed with commercial. The neighborhoods that contain the field include, from west to east, Koreatown, Westlake, Echo Park, Chinatown, Oil in the Los Angeles City field is relatively close to the surface. Every productive deposit has been in a geologic unit, the shallow Miocene-age Puente Formation. Covering the Puente Formation throughout most of the area is a layer of Pliocene- and Pleistocene-age alluvium. Three separate producing horizons, or vertical zones, are present in the Puente Formation, and are given numbers, First, Second. In addition to these zones, small pockets of oil have been throughout the upper part of the Puente. The average depth of the three zones from top to bottom is 900,1,100, and 1,500 feet, the field is split into three geographic zones, unrelated to the three vertical zones. The Western Area contains seeps that were known prehistorically, it is separated from the Central zone by a fault, Oil in the field is generally heavy, with API gravity averaging about 14, and ranging overall from 12 to 20. An early assessment by Paul Prutzman rated the quality of the oil from the field as low, due to the sulfur content
22.
Beverly Hills Oil Field
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The Beverly Hills Oil Field is a large and currently active oil field underneath part of the city of Beverly Hills, California, USA, and portions of the adjacent city of Los Angeles. Annual production from the field was 1, the three largest operators as of 2009 were independent oil companies Plains Exploration & Production, BreitBurn Energy, and Venoco, Inc. The field is long and narrow, about four miles long by a half-mile to mile across. From north to south the field is much narrower, extending near the middle of the field from near Monte Mar Drive in Los Angeles to about two blocks north of Olympic Blvd in Beverly Hills. The total productive area of the field, projected to ground surface, in most oil fields, wells are drilled at optimum spacing for petroleum extraction with the boreholes going straight down into the target formations. This facility also houses storage tanks, several oil-water separator units, a house, compressor house. A facility similar to the one adjacent to Beverly Hills High School, yet another drilling island, the largest of the four, containing over fifty active wells and operated by Plains Exploration & Production, is north of Pico between Genesee Avenue and Spaulding Avenue. This drilling island also contains wells that angle northeast into the Salt Lake Oil Field and this small drilling island includes 12 active wells directionally drilled into the Beverly Hills Oil Field, as well as several others drilled into the Cheviot Hills Field. The operators of a fifth drilling island, located at the corner of Avenue of the Stars and Constellation Boulevard in Century City. Originally constructed in the 1950s on what was then an unused back lot of Twentieth Century Fox Studios, its production declined in the 1970s. Land use changes and soaring real estate values contributed to its elimination, the city of Los Angeles handles all building permits and air permitting issues for the oil field. The field is an anticlinal structure with oil trapped by a combination of structural. Bounding the field on the south is the Brentwood-Las Cienegas Fault, the minimum depth to the larger deposits of profitably extractable oil varies from about 5600 to about 7,200 feet below ground surface, or 5400 to 7,000 feet below sea level. Oil in these sands is mainly found in structures, in which oil is trapped in more permeable sub-units within impermeable sands. Beneath the Ogden Sand is a nodular shale unit, also grouped with the Modelo, both the Ogden and the Hauser are richly productive, while a few oil-bearing pinch-outs are found in the D/M sand, which otherwise forms an impermeable cap to the Hauser. The deepest unit in the field which is being pumped is a portion of the Ogden Sands in the East Area of the field, discovered in 1967 and they do not state what percentage of that reserve is recoverable using current technologies. Oil was discovered in the northern Los Angeles basin in 1893, not far from the city center, and development of the Los Angeles City Oil Field was fast. In July 1900, W. W. Orcutt drilled into the Wolfskill zone of the Repetto Sands, about 2,500 feet below ground surface and it reached its peak production quickly, within two years of discovery, reporting 11.8 million barrels for 1968
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