Los Angeles Basin

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The Los Angeles Basin is the coastal sediment-filled plain located at the north end of the Peninsular Ranges province.^[1] in southern California, United States, and contains the central part of the city of Los Angeles as well as its southern and southeastern suburbs (both in Los Angeles and Orange counties). It is approximately 50 miles (80 km) long and 25 miles (40 km) wide, bounded on the north by the Santa Monica Mountains and San Gabriel Mountains, on the east by the Santa Ana Mountains and on the south by the Pacific Ocean and the Palos Verdes Hills, along the coast.^[2] The confluence of the Los Angeles and Rio Hondo rivers is the center of the basin.^[3]'

LA Basin Oil Fields, USGS

Los Angeles City oil field, 1905

Geology

Dominant structures in the basin are northwest-southeast trending fault zones causing parallel block faults causing topographic highs and deeper aniclinal structures in which oil fields are located.^[4] The principal subsidence and deposition occurred in the Upper Miocene until the Lower Pleistocene.^[5] The sediment in the basin is up to 6 miles (10 km) deep. The basin began to form during the Neogene approximately 15 million years ago (mya), when the terrain was underwater, during a crustal upheaval caused by a clockwise shift in the surrounding mountains. The underlying crustal weakening resulted in the formation of the large bowl of the basin. Sediment from the sea and rivers accumulated in the undersea bowl, building up in thick layers. Approximately 5 million years ago, the crustal stretching subsided and the ocean floor of the basin was forced to the surface. Additional sediment accumulated during the upswell resulting in the floor of the basin as it exists today.

Petroleum

The accumulation of fine-grained sediments with high organic content, interlayered with coarser grained sands, contributed to the formation of large deposits of oil, including the Wilmington Oil Field.^[6] Other large active oil fields include the Long Beach Oil Field, the Salt Lake Oil Field and South Salt Lake Oil Field, the Huntington Beach Oil Field, which underlies much of the city of Huntington Beach; and the Torrance Oil Field, adjacent to the Wilmington field on the northwest. Most of the numerous fields in the basin have either been abandoned or greatly scaled back in production since the early part of the 20th century. In the 1890s the oil field directly north of downtown Los Angeles, the Los Angeles City Oil Field, led the state of California in oil production.^[7] Some of the oil fields in the dense urban core remain productive, including the Beverly Hills Oil Field.^[8]

In 2013, the USGS estimated that the ten giant oilfields in the LA Basin have future potential to produce an additional 1.4 to 5.6 billion barrels of oil, with their best estimate being 3.2 billion barrels. The report acknowledges that only a fraction of this oil is likely to be produced, given the highly urbanized area surrounding the oilfields. ^[9]

Iodine

In former years iodine was recovered commercially from brine co-produced with oil. Dow Chemical Company operated a number of plants at oil fields in the Los Angeles Basin, and recovered iodine from brines that averaged 50 parts per million iodine. Production started in 1932 and lasted into the 1960s.^[10]

Earthquakes

Major faults include the Newport-Inglewood Fault, the Whittier Fault, the Santa Monica Fault, the Elsinore Fault Zone and the San Gabriel Fault.^[11] For a list of major events:

Significant LA earthquakes

Subsidence

Small-scale subsidence has occurred due to ground water withdrawal while large-scale subsidence has been the result of petroleum extraction, the most spectacular examples being the Baldwin Hills dam collapse of 1963 and the sinking of the Long Beach Harbor by several meters, since alleviated through water injection.^[12]

Los Angeles Basin
Downtown Los Angeles from the air

References

↑ Mayuga, M.N., Geology and Development of California's Giant-Wilmington Oil Field, in Geology of Giant Petroleum Fields, Tulsa: American Association of Petroleum Geologists, Memoir 14, pp. 160, 1970.
↑ Mayuga, M.N., Geology and Development of California's Giant-Wilmington Oil Field, in Geology of Giant Petroleum Fields, Tulsa: American Association of Petroleum Geologists, Memoir 14, pp. 160, 1970.
↑ "The Los Angeles Basin - A Huge Bowl of Sand". LAalmanac.com. Retrieved 2010-11-27. "The point where the Los Angeles and Rio Hondo Rivers merge in the City of South Gate is the geologic center for the Los Angeles Basin.'"
↑ Mayuga, M.N., Geology and Development of California's Giant-Wilmington Oil Field, in Geology of Giant Petroleum Fields, Tulsa: American Association of Petroleum Geologists, Memoir 14, pp. 160-161, 1970.
↑ Mayuga, M.N., Geology and Development of California's Giant-Wilmington Oil Field, in Geology of Giant Petroleum Fields, Tulsa: American Association of Petroleum Geologists, Memoir 14, pp. 161, 1970.
↑ Mayuga, M.N., Geology and Development of California's Giant-Wilmington Oil Field, in Geology of Giant Petroleum Fields, Tulsa: American Association of Petroleum Geologists, Memoir 14, pp. 162, 1970.
↑ History of Oil Production in California: California Department of Conservation, Department of Oil and Gas
↑ "Oil and Gas Statistics: 2007 Annual Report" (PDF). California Department of Conservation. December 31, 2007. Retrieved August 25, 2009.
↑ Remaining Recoverable Petroleum in Ten Giant Oil Fields of the Los Angeles Basin, Southern California, USGS, revised 2-2013
↑ G.I. Smith (1966) "Iodine" in Mineral Resources of California, California Division of Mines and Geology, Bulletin 191, p.198-199.
↑ Yerkes, R.F., McCulloh, T.H., Schoellhammer, J.E., and Vedder, J.G.,Geology of the Los Angeles Basin, Southern California, Washington: USGS Paper 420-A, p. A5 and A12, 1965.
↑ Mayuga, M.N., Geology and Development of California's Giant-Wilmington Oil Field, in Geology of Giant Petroleum Fields, Tulsa: American Association of Petroleum Geologists, Memoir 14, pp. 176-180, 1970.

v t e Greater Los Angeles Area

Central city	Los Angeles

Counties	Los Angeles Orange Riverside San Bernardino Ventura

Satellite cities	Long Beach Riverside San Bernardino

Cities >200k	Anaheim Irvine Santa Ana

Cities and towns 100k–200k	Burbank Corona Costa Mesa Downey East Los Angeles El Monte Fontana Fullerton Garden Grove Glendale Huntington Beach Inglewood Lancaster Moreno Valley Murrieta Norwalk Ontario Orange Oxnard Palmdale Pasadena Pomona Rancho Cucamonga Santa Clarita Simi Valley Temecula Thousand Oaks Torrance Ventura Victorville West Covina

Area regions	Antelope Valley Coachella Valley Conejo Valley Downtown Los Angeles East Los Angeles Gateway Cities Greater Hollywood Harbor Area High Desert Inland Empire Los Angeles metropolitan area Low Desert Northwest Los Angeles Palos Verdes Hills Pomona Valley San Bernardino Valley San Fernando Valley San Gabriel Valley Santa Ana Valley Santa Clarita Valley South Bay South Los Angeles Victor Valley Westside Los Angeles Wilshire

Landforms	Los Angeles Basin Baldwin Hills (range) Catalina Island Channel Islands Coachella Valley Morongo Basin San Fernando Valley San Bernardino Mountains San Gabriel Mountains San Jacinto Mountains Santa Ana Mountains Santa Monica Mountains Santa Susana Mountains Verdugo Mountains

Bodies of water	Los Angeles River Aliso Creek Arroyo Seco Ballona Creek Bell Creek Big Bear Lake Coyote Creek Lake Arrowhead Lake Gregory Lake Perris Lake Piru Malibu Creek Mojave River Pyramid Lake Rio Hondo San Gabriel River San Juan Creek San Pedro Bay Santa Ana River Santa Clara River Santa Margarita River Santa Monica Bay Soda Lake

v t e State of California

Sacramento (capital)

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Regions	Antelope Valley Big Sur California Coast Ranges Cascade Range Central California Central Coast Central Valley Channel Islands Coachella Valley Coastal California Conejo Valley Cucamonga Valley Death Valley East Bay (SF Bay Area) East County (SD) Eastern California Emerald Triangle Gold Country Great Basin Greater San Bernardino Inland Empire Klamath Basin Lake Tahoe Greater Los Angeles Los Angeles Basin Lost Coast Mojave Desert Mountain Empire North Bay (SF) North Coast North Coast (SD) Northern California Owens Valley Oxnard Plain Peninsular Ranges Pomona Valley Sacramento Valley Salinas Valley San Fernando Valley San Francisco Bay Area San Francisco Peninsula San Gabriel Valley San Joaquin Valley Santa Clara Valley Santa Clara River Valley Santa Clarita Valley Santa Ynez Valley Shasta Cascade Sierra Nevada Silicon Valley South Bay (LA) South Bay (SD) South Bay (SF) South Coast Southern Border Region Southern California Tech Coast Transverse Ranges Tri-Valley Victor Valley Wine Country

Metro regions	Metropolitan Fresno Los Angeles metropolitan area Greater Sacramento San Bernardino-RIverside metropolitan area San Francisco metropolitan area San Diego-Tijuana

Counties	Alameda Alpine Amador Butte Calaveras Colusa Contra Costa Del Norte El Dorado Fresno Glenn Humboldt Imperial Inyo Kern Kings Lake Lassen Los Angeles Madera Marin Mariposa Mendocino Merced Modoc Mono Monterey Napa Nevada Orange Placer Plumas Riverside Sacramento San Benito San Bernardino San Diego San Francisco San Joaquin San Luis Obispo San Mateo Santa Barbara Santa Clara Santa Cruz Shasta Sierra Siskiyou Solano Sonoma Stanislaus Sutter Tehama Trinity Tulare Tuolumne Ventura Yolo Yuba

Most populous cities	Los Angeles San Diego San Jose San Francisco Fresno Sacramento Long Beach Oakland Bakersfield Anaheim

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