Los Angeles Basin
The Los Angeles Basin (English. Los Angeles Basin ) is a plane and a sedimentary basin in Southern California in Los Angeles County and Orange County . The Los Angeles Basin is geographically bounded to the north by the Santa Monica Mountains and Puente Hills and to the east by the Santa Ana Mountains . In the west and south the plain ends at the Pacific Ocean . The basin is named after the city of Los Angeles , most of which is located in the basin, as well as numerous other cities, e.g. B. Beverly Hills . The Los Angeles Basin is an economically important oil reservoir.
Emergence
The Los Angeles Basin is geologically relatively young. It began to form around 16 million years ago. It was created as part of the formation of the San Andreas Trench system . When the mountain range of the Transverse Ranges broke off from the Peninsular Ranges and migrated north through the plate tectonics of the Pacific Plate , turning 110 degrees in the process, a gap was created. This was initially closed by volcanic rock from volcanoes of the Glendora - El Modeno volcanism, but then filled with sediments .
The igneous rock formed by the Glendora-Modeno volcanism consists mainly of basalt and tuff and can be detected today in the north and northeast of the basin. The age varies between 18 and 15 million years. During the late Miocene and early Pliocene , the San Andreas Rift shifted and the transversal ranges increased significantly as a result. As a result, a lot of sediment was carried into the submarine basin at that time.
Seismics
The Los Angeles Basin is part of the Pacific Ring of Fire . The San Andreas Trench runs a little further east through the San Gabriel Mountains . As an area located on the collusion zone of the North American Plate and the Pacific Plate , the basin is seismically very active and criss-crossed by several faults and the site of frequent earthquakes . The first documented earthquake in the Los Angeles Basin occurred on August 1, 1769 at around 10 a.m. while the Portola expedition camped on a river. Two aftershocks followed . On September 24, 1827, an earthquake with a weight of probably 5.5 struck what was then Pueblo Los Angeles. A later earthquake with the epicenter in the Los Angeles Basin was the Long Beach earthquake in 1933, which caused damage as far as east Los Angeles. The quake caused mostly brick- built buildings to collapse and resulted in the 1933 Field Act , a law designed to ensure that school buildings in California were earthquake-proof.
Oil production
The oil in the Los Angeles Basin was and is an important economic factor in the development of today's metropolis since oil production began in the 1870s. The oil industry still employs around 80,000 people in Los Angeles County. There are 68 oil fields . One special feature is oil production in an urban environment. It is the largest such oil production. On the other hand, the oil industry is characterized by the direct connection between production and refining. Petroleum refineries , such as the one in El Segundo , are connected to oil wells by underground pipelines .
literature
- Arthur Gibbs Sylvester / Elizabeth O'Black, Roadside Geology of Southern California , Mountain Press Publishing, Missoula ( Montana ) 2016, ISBN 9780878426539
Web links
Individual evidence
- ^ A b Arthur Gibbs Sylvester / Elizabeth O'Black Gans, Roadside Geology of Southern California , Mountainpress Publishing, Missoula 2016, pp. 200–223.
- ^ Thane H. McCulloh, Robert J. Fleck, Rodger E. Denison, Larry A. Beyer, Richard G. Stanley, Age and Tectonic Significance of Volcanic Rocks in the Northern Los Angeles Basin, California US Geological, 2002
- ↑ Abraham Hoffmann: California's Deadliest Earthquakes , The History Press, Charleston (South Carolina) 2017, ISBN 9781467136020 . P. 16.
- ↑ Abraham Hoffmann: California's Deadliest Earthquakes , The History Press, Charleston (South Carolina) 2017, ISBN 9781467136020 . P. 20.
- ↑ Abraham Hoffmann: California's Deadliest Earthquakes , The History Press, Charleston (South Carolina) 2017, ISBN 9781467136020 . Pp. 69-76.
- ↑ Matt Jaffe, Above the Surface and Below, LA Is Still an Oil Town , Los Angeles Magazine, February 5, 2018.