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83-544: The Salton Buttes are a group of volcanoes in Southern California , on the Salton Sea . They consist of a 7-kilometer (4.3 mi)-long row of five lava domes, named Mullet Island, North Red Hill, Obsidian Butte, Rock Hill and South Red Hill. They are closely associated with a fumarolic field and a geothermal field , and there is evidence of buried volcanoes underground. In pre-modern times Obsidian Butte

166-419: A volcanic vent 250 m (820 ft) wide Obsidian Butte is surrounded by a lava flow , and Mullet Island has a characteristic "onion-skin" foliation . On Red Hill, there is a quarry , a marina , and a trailer park , and Obsidian Butte has been extensively quarried, to the point that it has lost most of its original appearance. There are hot springs and mofettes on Mullet Island. A fumarole field

249-644: A California earthquake forecast, which models earthquake occurrence in California. This is a partial list of earthquakes in Southern California. For a full list, see List of earthquakes in California . Note: Earthquakes with epicenters in the Los Angeles Metro Area are marked with the (#) symbol. Other earthquakes mentioned indicates shaking was felt in the region. As of the 2020 United States Census , Southern California has

332-658: A M w   6.7 earthquake or greater, such as the San Andreas Fault , which can produce M w   8.0 or greater. The largest known earthquake in California was the 1857 Fort Tejon earthquake that ruptured 200+ miles (320+ kilometers) of the San Andreas Fault from Parkfield to Wrightwood . With a recurrence interval of roughly 150 years, this part of the San Andreas fault is well within its window to produce another large earthquake. Along with

415-474: A former floodplain can be the result of either changes in sea level , local or regional tectonic uplift ; changes in local or regional climate; changes in the amount of sediment being carried by the river or stream; change in discharge of the river; or a complex mixture of these and other factors. The most common sources of the variations in rivers and streams that create fluvial terraces are vegetative, geomorphic, and hydrologic responses to climate. More recently,

498-595: A higher population, with 23.76 million residents as of the 2020 census . The sparsely populated desert region of California occupies a significant portion (part of which has even been proposed to be split into a new county due to cultural, economic and geographic differences relative to the rest of the more urban region) of the area: the Colorado Desert , along with the Colorado River , is located on Southern California's eastern border with Arizona , and

581-611: A population of 23,762,904. Despite a reputation for high growth rates, Southern California's population has grown slower than the state average since the 2000s. This is due to California's growth becoming concentrated in the northern part of the state as result of a stronger, tech-oriented economy in the Bay Area and an emerging Greater Sacramento region. Southern California consists of one Combined Statistical Area , eight Metropolitan Statistical Areas , one international metropolitan area , and multiple metropolitan divisions. The region

664-473: A population of approximately 4 million, 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 approximately 1.4 million is San Diego, the second most populous city in the state and the eighth most populous in the nation. The counties of Los Angeles , San Diego , Orange , Riverside , and San Bernardino are

747-840: A total heat output of 1,000–10,000 MW (1,300,000–13,400,000 hp). Part of this heat output is used to generate geothermal power , with annual production of 1–3 TWh/a (110–340 MW). The Salton Buttes volcanoes were formed on Quaternary sediments of the Colorado River Delta . Below them, the basement is rock formed from sediments deposited in lakes and by rivers, such as mudstones , sandstones and siltstones . Below this 5 km (3.1 mi) thick upper layer, there are metamorphic greenschist rocks formed by hydrothermal alteration and thermal metamorphism of sediments, and finally, below that, gabbroic rocks, at 18–10 km (11.2–6.2 mi) depth. Diabase and intruded rhyolites have also been identified in

830-769: A whole enacted the Alquist Priolo Special Studies Zone Act in the wake of the 1971 San Fernando earthquake . The act prohibits new construction of residential buildings closer than 50 feet (15 m) from a surface rupturing active fault zone. In addition, the act improved safety by requiring new structures (both residential and commercial) to be seismically retrofitted. It also required existing infrastructure to comply. Since 1972, numerous large magnitude earthquakes have struck Southern California with little widespread damage in part due to act. However, exceptions can be noted for epicenters that lie directly on top of densely populated regions such as

913-804: Is a geographic and cultural region that generally comprises the southern portion of the U.S. state of California . It includes the Los Angeles metropolitan area (the second most populous urban agglomeration in the United States ) as well as the Inland Empire (another large metropolitan area). The region generally contains ten of California's 58 counties: Los Angeles , San Diego , Orange , Riverside , San Bernardino , Kern , Ventura , Santa Barbara , San Luis Obispo , and Imperial counties. Although geographically smaller than Northern California in land area, Southern California has

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996-502: Is also home to a large surf and skateboard culture. Companies such as Vans , Volcom , Quiksilver , No Fear , Stüssy , RVCA , and Body Glove are all headquartered there. Skateboarder Tony Hawk ; surfers Rob Machado , Timmy Curran , Bobby Martinez , Pat O'Connell , Dane Reynolds , and Chris Ward live in Southern California. Some of the most famous surf locations are in Southern California as well, including Trestles , Rincon , The Wedge , Huntington Beach , and Malibu . Some of

1079-513: Is also known for its mountain resort communities, such as Big Bear Lake , Lake Arrowhead , and Wrightwood , and their ski resorts, like Bear Mountain , Snow Summit , Snow Valley Mountain Resort , and Mountain High . The inland desert city of Palm Springs is also popular. Southern California is generally considered the area of California south of the latitude 35°45', approximately one-third of

1162-687: Is an important government, arts and entertainment, and retail district. Downtown San Diego is the CBD of San Diego, though the city is filled with business districts. These include Carmel Valley , Del Mar Heights , Mission Valley , Rancho Bernardo , Sorrento Mesa , and University City . Most of these districts are located in Northern San Diego and some within North County regions. Los Angeles Orange County Riverside & San Bernardino San Diego Southern California

1245-553: Is associated with the Salton Buttes. The field is characterized by gryphons and salses . These exhale carbon dioxide and steam , as well as ammonia and hydrogen sulfide . Some of these fumarolic vents reach heights of 2 m (6.6 ft), and resemble the lava-erupting vents. Mud pots are also found. Parts of the field have recently emerged from the Salton Sea, due to dropping water levels, which have also caused

1328-410: Is home to Los Angeles International Airport , the second-busiest airport in the United States by passenger volume (see World's busiest airports by passenger traffic ) and the third-busiest by international passenger volume (see Busiest airports in the United States by international passenger traffic ); San Diego International Airport , the busiest single-runway airport in the world; Van Nuys Airport ,

1411-568: Is home to two extended metropolitan areas that exceed five million in population. These are the Greater Los Angeles Area at 17,786,419, and San Diego–Tijuana at 5,105,768. Of these metropolitan areas, the Los Angeles-Long Beach-Santa Ana metropolitan area , Riverside-San Bernardino-Ontario metropolitan area , and Oxnard-Thousand Oaks-Ventura metropolitan area form Greater Los Angeles; while

1494-401: Is low to moderate depending on the area. Rain is infrequent, but is often heavy when it does occur, making flash floods an aspect of living in Southern California. This climatic pattern was alluded to in the hit song " It Never Rains (In Southern California) ". While snow is very rare in lower elevations, mountains above 5,000 feet (1,500 m) receive plentiful snowfall in the winter. Since

1577-399: Is needed for this process). Although this is the first step to the process for the formation of a marine terrace, not all wave cut platforms will become a marine terrace. After the wave cut platform is formed it must be removed from interaction with the high wave energy. This process happens by either change in sea level due to glacial-interglacial cycles or tectonically rising landmasses. When

1660-417: Is only found in archeological sites from the late Holocene . Obsidian hydration dating on the Salton Buttes yielded ages of 8,400 - 2,500 years ago, while thermoluminescence dating at Obsidian Butte has yielded an age of 3,300 ± 500 years ago, both implying recent ages. An even more recent age for Obsidian Butte is 490 BCE . The discovery of the exact age of Obsidian Butte is of archeological importance, as

1743-649: Is unclear: both deep mafic and shallow felsic sources have been proposed. Seismic tomography of the area below the Salton Buttes has identified areas in the mantle with an anomalously low seismic velocities, which would be consistent with higher temperatures there. The domes are formed by rhyolite , which has an alkaline and calcium -poor composition and defines a potassium -rich suite (see QAPF diagram ). Scarce phenocrysts include amphibole , anorthoclase , apatite , clinopyroxene , ilmenite , magnetite , orthopyroxene , quartz and zircon . The isotopic composition of these volcanic rocks differs from that of

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1826-605: The El Centro metropolitan area and San Diego-Carlsbad-San Marcos metropolitan area form the Southern Border Region . North of Greater Los Angeles are the Santa Barbara , San Luis Obispo , and Bakersfield metropolitan areas. Los Angeles (with a population of approximately 3.9 million people) and San Diego (at nearly 1.4 million people) are the two largest cities in all of California, and are among

1909-781: The Gulf of California and the East Pacific Rise . The northernmost segment of the East Pacific Rise appears to be identical to the Brawley Seismic Zone . Most of the Buttes formed between 1,800 and 2,300 years ago, although Mullet Island may be 5,000 years older. According to the Global Volcanism Program , Mullet Island formed 290 BCE ± 100 years, Obsidian Butte 10 CE ± 100 years and the other Buttes 210 CE ± 100 years. If Mullet Island formed at

1992-650: The Los Angeles metropolitan area ( Los Angeles and Orange counties, with 13.3 million people), the Inland Empire ( Riverside and San Bernardino counties, including the Coachella Valley cities, with 4.3 million people), and the Oxnard–Thousand Oaks–Ventura metropolitan area (0.8 million people). In addition, Southern California contains the San Diego metropolitan area with 3.3 million people, Bakersfield metro area with 0.9 million, and

2075-717: The Mojave Desert shares a border with Nevada to the northeast. Southern California's southern border with Baja California is part of the Mexico–United States border . Southern California encompasses eight metropolitan areas (MSAs), three of which together form the Greater Los Angeles Combined Statistical Area (CSA) with over 18 million people, the second-biggest CSA after the New York CSA . These three MSAs are

2158-760: The Newport–Inglewood-Rose Canyon Fault (located adjacent to SoFi Stadium and responsible for Signal Hill ), the Elsinore Fault (created Lake Elsinore ), the Garlock Fault (which marks boundary between of the Sierra Nevada and the Mojave Desert ), and the Hollywood fault (which is within feet of Capitol Records and is roughly parallel to Hollywood Boulevard ). The United States Geological Survey (USGS) has released

2241-581: The Pliocene , the Salton Trough and the Gulf of California have formed an active rift zone south of the San Andreas Fault . In a rift zone, seafloor spreading is underway, accompanied by volcanic and geothermal activity, active faulting and rapid sedimentation . Since five million years ago, the buildup of sediments in the Colorado River Delta separated the Salton Trough area from

2324-587: The Salton Sea , with their peaks at an elevation of −40 m (−130 ft), in Imperial County, California . The towns of Niland and Calipatria lie northeast and southeast of the Salton Buttes, respectively, and Palm Springs is 140 kilometers (90 mi) northwest. The Alamo River enters the Salton Sea between the Salton Buttes. The name "Niland Field" has also been applied to the system. Download coordinates as: The Salton Buttes are five lava domes that rise 30–40 m (98–131 ft) above

2407-779: The San Diego metropolitan area as they do with the Inland Empire . To the east, the United States Census Bureau considers the San Bernardino and Riverside County areas, Riverside-San Bernardino area as a separate metropolitan area from Los Angeles County. Newly developed exurbs formed in the Antelope Valley , north of Los Angeles, the Victor Valley , and the Coachella Valley with the Imperial Valley . Also, population growth

2490-492: The San Fernando Valley . The area of Santa Monica and Venice (and perhaps some of Culver City) is informally referred to as "Silicon Beach" because of the concentration of financial and marketing technology-centric firms located in the region. The San Bernardino-Riverside Area maintains the business districts of Downtown San Bernardino , Hospitality Business/Financial Centre , University District which are in

2573-480: The Santa Barbara , San Luis Obispo , and El Centro (Imperial County) metropolitan areas. The Southern California Megaregion (or megalopolis ) is larger still, extending northeast into Las Vegas , Nevada and south across the Mexican border into Tijuana . Within Southern California are two major cities, Los Angeles and San Diego , as well as three of the country's largest metropolitan areas . With

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2656-526: The Transverse and Peninsular Ranges with their peaks, and into the large and small interior valleys, to the vast deserts of California . Note: Plate boundary faults are indicated with a (#) symbol. Each year, Southern California has about 10,000 earthquakes. Nearly all of them are too small to be felt. Only several hundred have been greater than magnitude (M w  ) 3.0, and only about 15–20 have been greater than M w   4.0. California as

2739-403: The entertainment industry . Other industries include software, automotive, aerospace, finance, biomedical, ports and regional logistics. The region was a leader in the housing bubble from 2001 to 2007, and has been heavily impacted by the housing crash. Since the 1920s, motion pictures, petroleum, and aircraft manufacturing have been major industries. In one of the richest agricultural regions in

2822-546: The Los Angeles Area are the major business districts of Downtown Pasadena , Downtown Burbank , Downtown Santa Monica , Downtown Glendale and Downtown Long Beach . Los Angeles proper has many business districts, such as Downtown LA and those lining Wilshire Boulevard , including Mid-Wilshire , the Miracle Mile , Downtown Beverly Hills , and Westwood ; others include Century City and Warner Center in

2905-399: The M w   6.7 1994 Northridge Earthquake and, to a lesser extent, the smaller M w   5.5 2008 Chino Hills earthquake . The Northridge earthquake occurred on a blind-thrust fault directly underneath the San Fernando Valley , which until the earthquake was previously undiscovered. Seismic retrofitting of existing and new construction is aimed to prevent damage and save lives in

2988-503: The Obsidian Butte was accessible. The domes were formed by effusive eruptions , but at least Obsidian Butte and South Red Hill also experienced explosive eruptions , which at Obsidian Butte preceded the effusive eruption stage. These explosive eruptions deposited pumice and tephra , which were encountered in drill cores in the area, and have also been quarried . Tuffs found farther south, at Cerro Prieto, have been linked to

3071-411: The Salton Buttes were formerly considered to be of the late Pleistocene epoch (which ended with the end of the last glacial maximum ), newer dating efforts have determined that all of them formed more recently, during the current Holocene epoch, mostly through effusive eruptions . Future eruptions are possible and could endanger the surroundings. The Salton Buttes lie on the southeastern shores of

3154-539: The Salton Buttes, but the large distance makes such a link questionable. After their emplacement, the Salton Buttes were at times submerged in Lake Cahuilla , causing the formation of wave cut terraces and rendering the obsidian of Obsidian Butte inaccessible. However, only South Red Hill appears to have erupted underwater. Pumice rafts formed on the lake and are now preserved on its former shorelines. Wind-borne and lacustrine sediments were also emplaced on

3237-511: The Salton Trough sediments. The total volume of the domes is about 0.5 km (0.12 cu mi). Obsidian from Obsidian Butte has been identified in distant archeological sites . It has been found in sites in the Colorado Desert , across San Diego County and across northern Mexico and the Southwestern United States . Before Obsidian Butte was emplaced and thus became available for obsidian production, people in

3320-456: The Southern California desert system. Because of the barrier formed by the Tehachapi and Sierra Nevada ranges, cartographer George Wheeler observed in 1876 that Northern California was better connected to Oregon and Nevada than it was to Southern California. Following the acquisition of the territory of California by the United States, several pro-slavery politicians attempted to arrange

3403-493: The U.S., cattle and citrus were major industries until farmlands were turned into suburbs. Although military spending cutbacks have had an impact, aerospace continues to be a major factor. Southern California is home to many major business districts. Central business districts (CBD) include Downtown Los Angeles , Downtown Riverside , Downtown San Bernardino , downtown San Diego , and the South Coast Metro . Within

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3486-537: The actual Gulf of California , forming a large depression that currently reaches a depth of 40 m (130 ft) below sea level. This depression is a pull-apart basin . It has formed between various branches of the San Andreas Fault and the San Jacinto Fault (which are connected by the Brawley Seismic Zone ) The Salton Trough is still actively subsiding at rates of 3 mm/a (0.12 in/year), increasing to 4–8 mm/a (0.16–0.31 in/year) in

3569-432: The aftermath of a major quake, but it cannot guarantee that buildings will be unscathed if the epicenter is relatively close by. The 1994 Northridge earthquake was particularly destructive, causing a substantial number of deaths, injuries, and structural collapses. The quake caused the most property damage of any earthquake in U.S. history at an estimated $ 20 billion. Many Southern California faults are able to produce

3652-468: The area in 2010), the Salton Buttes are considered high-hazard volcanoes. Future eruptions may generate pyroclastic flows and pyroclastic surges , which could endanger people within ten kilometers (6.2 mi) of the vents. The field is monitored with seismometers and periodic sampling of gas exhalations and hot springs; there is a volcano hazard map, but it is incomplete. Southern California Southern California (commonly shortened to SoCal )

3735-553: The buttes, the Red Hills and Obsidian Butte are the largest. The Red Hills are a paired volcano, connected through pyroclastic deposits. The Red Hills are also known collectively as Red Island; Red Island and Mullet Island were both islands in 2005. As of 2018, Mullet Island is a peninsula . The other domes have also been islands at times, and waves have cut erosional terraces along the former shorelines. The Salton Buttes are lava domes . They formed from viscous lava rising in

3818-555: The centers of their respective metropolitan areas, composed of numerous smaller cities and communities. The urban area is also host to an international San Diego–Tijuana metropolitan region, created by the urban area spilling over into Baja California . The main barrier to urbanization along the Interstate 5 corridor is Camp Pendleton . The cities and communities along Interstate 15 and Interstate 215 are so interrelated that Temecula and Murrieta have as much connection with

3901-522: The central area of the Trough. A number of Quaternary volcanic centers have formed in the region, including Cerro Prieto , Consag Rock , Isla San Luis , Isla Tortuga , the Salton Buttes and Sierra Pinacate which is the largest of these volcanoes. Strong geothermal activity has been observed as well, with the Salton Trough alone hosting five geothermal fields ( Brawley -Mesquite, Cerro Prieto , East Mesa, Heber and Salton Sea). These five fields have

3984-612: The cities of San Bernardino and Riverside. In Orange County, has highly developed suburban business centers (also known as edge cities ) including the Anaheim–Santa Ana edge city along I-5; and another, the South Coast Plaza–John Wayne Airport edge city that stretches from the South Coast Metro to the Irvine Business Complex ; Newport Center ; and Irvine Spectrum . Downtown Santa Ana

4067-462: The direct modification of rivers and streams and their watersheds by cultural processes have resulted in the development of terraces along many rivers and streams. Kame terraces are formed on the side of a glacial valley and are the deposits of meltwater streams flowing between the ice and the adjacent valley side. A marine terrace represents the former shoreline of a sea or ocean. It can be formed by marine abrasion or erosion of materials comprising

4150-594: The division of Alta California at 36 degrees, 30 minutes, the line of the Missouri Compromise . Instead, the passing of the Compromise of 1850 enabled California to be admitted to the Union as a free state , preventing the southern half of California from becoming its own separate slave state . Subsequently, Californians (dissatisfied with inequitable taxes and land laws) and pro-slavery Southerners in

4233-581: The domes. The discovery of Holocene eruptions of the Salton Buttes have drawn attention to the volcanic hazards posed by the field. The Salton Buttes are monitored by the California Volcano Observatory for possible future volcanic activity. Geophysical evidence shows that liquid magma is still present underneath the Salton Buttes. Since the volcanoes have erupted in the past, there is present-day unrest, and there are areas of high population density nearby (about 2,518 people lived in

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4316-435: The existence of a continuously active deep magmatic reservoir , which generates precursor magmas and episodically delivers them to a shallower magmatic reservoir, where the rhyolites are formed. Xenoliths found in the volcanic rocks include granite , granophyre , metasediments and tholeiite , often heavily altered by interactions with the volcanic system. Some of these basalts resemble those from active rift zones in

4399-429: The first decade of the 21st century, droughts and wildfires have increased in frequency as a result of climate change . Southern California consists of one of the more varied collections of geologic, topographic, and natural ecosystem landscapes in a diversity outnumbering other major regions in the state and country. The region spans from Pacific Ocean islands , shorelines , beaches, and coastal plains , through

4482-749: The five most populous in the state, and are among the top 15 most populous counties in the United States. The motion picture , television and music industry are centered in the Los Angeles area in Southern California. Hollywood , a district of Los Angeles, gives its name to the American motion picture industry, which is synonymous with the neighborhood name. Headquartered in Southern California are The Walt Disney Company (which owns ABC ), Sony Pictures , Universal Pictures , MGM , Paramount Pictures , and Warner Bros . Universal, Warner Bros., and Sony also run major record companies. Southern California

4565-553: The fumarolic vents to develop and grow noticeably, including an increased number of gryphons. There is a geothermal field associated with the Salton Buttes. It is one of the largest and warmest on Earth, with temperatures of 360 °C (680 °F) at 1.5–2.5 km (0.93–1.55 mi) depth. Various volcanic rocks have been found in drill cores at the Salton Buttes. Rocks found include andesite , basalt , dacite , diabase , gabbro and rhyolite . Some of these volcanic rocks bear traces of hydrothermal alteration . In some places

4648-499: The granites formed much more recently and are among the youngest known granites on Earth. Radiometric dating of zircons found in the volcanic rocks and xenoliths as well as other methods, however, indicated that volcanic activity was much more recent, latest Pleistocene - Holocene . This recent conclusion was also supported by the fact that the small domes are located in a high sedimentation rate setting and would have been buried if they were too old and that obsidian from Obsidian Butte

4731-561: The layers of volcanic rocks are as thick as 100 m (330 ft). There may be other volcanoes buried in the sediment pile; at least four separate aeromagnetic anomalies have been found at the Salton Buttes, and these may be signs of buried volcanoes. The field has been prospected for geothermal power generation, and presently eleven geothermal power plants in the Imperial Valley Geothermal Project have capacity to produce 432 megawatts of power. Since

4814-582: The lightly populated "cow counties" of Southern California attempted three times in the 1850s to achieve a separate statehood or territorial status separate from Northern California . The last attempt, the Pico Act of 1859, was passed by the California State Legislature and signed by State Governor John B. Weller . It was approved overwhelmingly by nearly 75 percent of voters to form the proposed Territory of Colorado . This territory

4897-550: The more urban region) that have been left undeveloped. It is the third most populated megalopolis in the United States, after the Great Lakes megalopolis and the Northeast megalopolis . Much of Southern California is famous for its large, spread-out, suburban communities and use of automobiles and highways. The dominant areas are Los Angeles, Orange County , San Diego , and Riverside – San Bernardino , each of which are

4980-591: The other line connecting San Bernardino, Riverside, and Orange counties directly. Southern California is also home to the Port of Los Angeles , the country's busiest commercial port; the adjacent Port of Long Beach , the country's second busiest container port; and the Port of San Diego . The following table shows all airports listed by the Federal Aviation Association (FAA) as a hub airport: Terrace (geology) The sediments underlying

5063-447: The presence of Obsidian Butte obsidians in an archeological site would imply that the site must post-date the eruption of Obsidian Butte. The emplacements of Obsidian Butte and Red Hill probably occurred within a short time — less than five centuries apart. Based on C-14 dating of present Obsidian Butte artifacts, it has been found that the interval from which these were harvested was between 510 BCE to 640 CE further signifying at which time

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5146-475: The region used obsidian from the Coso volcanic field ; this trend away from Coso towards Obsidian Butte was recognized even before the exact timing of the Obsidian Butte eruption was known. How the magmas are formed is controversial. Explanations have called on several different processes, including assimilation of hydrothermally altered rocks, fractional crystallization and partial melting . One model presumes

5229-473: The relict bottom of these lakes. Finally, glaciolacustrine kame terraces are either the relict deltas or bottoms of ancient ice marginal lakes. In geomorphology, a structural terrace is a terrace created by the differential erosion of flat-lying or nearly flat-lying layered strata. The terrace results from preferential stripping by erosion of a layer of softer strata from an underlying layer of harder strata. The preferential removal of softer material exposes

5312-513: The same time as the other Buttes, the eruption episode that formed the Salton Buttes lasted probably no more than 500 years. Presently, fumarolic activity occurs at the Buttes from cracks in the volcanic rocks of the Salton Buttes and seismic activity has been recorded from the geothermal field. Various ages have been inferred for the Salton Buttes with various dating techniques. Early potassium-argon dating at Obsidian Butte yielded an age of 55,000 – 16,000 years before present but this estimate

5395-470: The sediments. All of the Salton Buttes, except for Mullet Island, have developed on a lineament , a linear feature with a conspicuous magnetic anomaly . The volcanoes seem to share a common feeder dyke . This dyke may be connected to deep-seated extensional processes along a transform fault that links the San Andreas Fault to the Gulf of California. The source of heat for the volcanoes and geothermal field

5478-459: The shallow-water to slightly emerged environments, or some combination of these. Given the smaller size of lakes relative to the size of typical marine water bodies, lake terraces are overall significantly narrower and less well developed than marine terraces. However, not all lake terraces are relict shorelines. In case of the lake terraces of ancient ice-walled lakes, some proglacial lakes, and alluvium-dammed (slackwater) lakes, they often represent

5561-443: The shoreline (marine-cut terraces or wave-cut platforms ); the accumulations of sediments in the shallow-water to slightly emerged coastal environments (marine-built terraces or raised beach ); or the bioconstruction by coral reefs and accumulation of reef materials (reef flats) in intertropical regions. The formation of a marine terrace follows this general process: A wave cut platform must be carved into bedrock (high wave energy

5644-471: The sole county to vote for the GOP, with Orange County having been Democrat since 2012. Southern California is one of the largest economies in the United States. It is dominated by, and heavily dependent upon, the abundance of petroleum, as opposed to other regions where automobiles are not nearly as dominant, due to the vast majority of transport that runs on this fuel. Southern California is famous for tourism and

5727-517: The southern section of the San Andreas (in the Palm Springs region, which has not ruptured in ~400 years), the entire Southern California portion of the San Andreas Fault is ready to produce a powerful earthquake in the near future. Notable faults capable of large magnitude events include the San Jacinto Fault (a splay of the San Andreas that runs directly under the I-10 & I-215 interchange),

5810-470: The state, formed by the northern boundaries of San Luis Obispo , Kern , and San Bernardino counties, which are not exactly a straight line. Another definition for Southern California uses Point Conception and the Tehachapi Mountains as the northern geographical barriers, especially when defining California's bioregions . In this definition, Owens Valley and Death Valley are part of

5893-993: The surrounding terrain. Each peak is no wider than 1 km (0.62 mi), but together they form a chain 7 km (4.3 mi) long. From north to south, they are named Mullet Island ( 33°13′32″N 115°36′30″W  /  33.22556°N 115.60833°W  / 33.22556; -115.60833  ( Mullet Island ) ), North Red Hill ( 33°12′0″N 115°36′43″W  /  33.20000°N 115.61194°W  / 33.20000; -115.61194  ( North Red Hill ) ), South Red Hill ( 33°11′46″N 115°36′42″W  /  33.19611°N 115.61167°W  / 33.19611; -115.61167  ( South Red Hill ) ), Rock Hill ( 33°11′1″N 115°37′24″W  /  33.18361°N 115.62333°W  / 33.18361; -115.62333  ( Rock Hill ) ) and Obsidian Butte ( 33°10′17″N 115°38′16″W  /  33.17139°N 115.63778°W  / 33.17139; -115.63778  ( Obsidian Butte ) ). Of

5976-417: The top eight largest cities in the United States. In Southern California, there are also 14 cities with more than 200,000 residents and 48 cities over 100,000 residents. Many of Southern California's most developed cities lie along or in close proximity to the coast, with the exception of San Bernardino and Riverside. Southern California has drifted left since 2004, and is solidly Democrat. Kern County remains

6059-415: The tread and riser of a terrace are also commonly, but incorrectly, called terraces, leading to confusion. Terraces are formed in various ways. Fluvial terraces are remnants of the former floodplain of a stream or river. They are formed by the downcutting of a river or stream channel into and the abandonment and lateral erosion of its former floodplain. The downcutting, abandonment, and lateral erosion of

6142-413: The wave cut has been raised above sea level it is preserved. The terraces are most commonly preserved in flights along the coastline. A lake (lacustrine) terrace represents the former shoreline of either a nonglacial, glacial, or proglacial lake . As with marine terraces, a lake terrace can be formed by either the abrasion or erosion of materials comprising the shoreline, the accumulations of sediments in

6225-429: The world's busiest general aviation airport; major commercial airports at San Bernardino , Orange County , Bakersfield , Ontario , Burbank , and Long Beach ; and numerous smaller commercial and general aviation airports. Six of the seven lines of the commuter rail system, Metrolink , run out of Downtown Los Angeles, connecting Los Angeles, Ventura , San Bernardino, Riverside, Orange, and San Diego counties with

6308-435: The world's largest action sports events, including the X Games , Boost Mobile Pro , and the U.S. Open of Surfing , are held in Southern California. The region is also important to the world of yachting with premier events including the annual Transpacific Yacht Race , or Transpac , from Los Angeles to Hawaii. San Diego Yacht Club hosted the three America's Cup races from 1988 to 1995. The first modern-era triathlon

6391-513: Was an important regional source of obsidian . The Salton Buttes lie within the Salton Trough , a tectonic depression formed by the San Andreas Fault and the San Jacinto Faults . The depression forms the northward extension of the Gulf of California , and is separated from it by the Colorado River Delta . A number of geothermal and volcanic features are located in the area, which is a region of active seafloor spreading . While

6474-528: Was grouped with other counties of the San Joaquin Valley , California's central agricultural valley. Southern California consists of a heavily developed urban environment, home to some of the largest urban areas in the state, along with the Deserts of California (part of which was even proposed to become a new county due to cultural, economic and geographic differences relative to the rest of

6557-590: Was held in San Diego's Mission Bay in 1974. Since then, Southern California, and San Diego in particular, have become a mecca for triathlon and multi-sport racing, products, and culture. Southern California has multiple sports franchises and networks, such as Fox Sports Net . Many of these locals and tourists frequent the Southern California coast for its beaches. Some of Southern California's most popular beaches are Malibu , Laguna Beach , La Jolla , Manhattan Beach , and Hermosa Beach . Southern California

6640-546: Was high in the Bakersfield-Kern County , Santa Maria , and San Luis Obispo areas. Most of Southern California has a Mediterranean -like climate, with warm and dry summers, mild and wet winters, where cool weather and freezing temperatures are rare. Southern California contains other types of climates, including semi-arid , desert and mountain , with infrequent rain and many sunny days. Summers are hot or warm, and dry, while winters are mild, and rainfall

6723-534: Was later supplanted by another age estimate of 33,000 ± 35,000 years ago. Other proposed ages were 33,000 ± 18,000 and less than 10,000 years ago, and archeomagnetic methods concluded that the Salton Buttes were not simultaneously active with Cerro Prieto or Crater Elegante in the Sierra Pinacate. Subsurface volcanic rocks at the Salton Buttes have been dated to 3.8 ± 0.4 million years ago, 960,000 ± 190,000 years ago and 479,000 – 420,000 years ago, but some of

6806-698: Was the name of a proposed new state which failed to get on the 2018 California ballot. The ballot measure proposed splitting the existing state into three parts. In December 2020, during the COVID-19 pandemic , the state government led by Governor Gavin Newsom divided the state into five regions for the purpose of issuing stay-at-home orders. The Southern California region consisted of the following counties: Imperial , Inyo , Los Angeles , Mono , Orange , Riverside , San Bernardino , San Diego , San Luis Obispo , Santa Barbara , and Ventura . However, Kern County

6889-773: Was to include a portion of the much larger Tulare County and all of San Luis Obispo County . The proposal was sent to Washington, D.C. , with a strong advocate in Senator Milton Latham . However, the secession crisis following the election of Abraham Lincoln in 1860 and the subsequent American Civil War led to the proposal never coming to a vote. In 1900, the Los Angeles Times defined Southern California as including "the seven counties of Los Angeles, San Bernardino, Orange, Riverside, San Diego, Ventura, and Santa Barbara." This definition left out San Luis Obispo and Kern counties. Southern California

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