The Salton Trough is an active tectonic pull-apart basin, or graben. It lies within the

Imperial Imperial is that which relates to an empire, emperor, or imperialism. Imperial or The Imperial may also refer to: Places United States * Imperial, California * Imperial, Missouri * Imperial, Nebraska * Imperial, Pennsylvania * Imperial, Texas ...

Riverside Riverside may refer to: Places Australia * Riverside, Tasmania, a suburb of Launceston, Tasmania Canada * Riverside (electoral district), in the Yukon * Riverside, Calgary, a neighbourhood in Alberta * Riverside, Manitoba, a former rural ...

, and San Diego counties of southeastern California, United States and extends south of the

Mexico–United States border The Mexico–United States border ( es, frontera Estados Unidos–México) is an international border separating Mexico and the United States, extending from the Pacific Ocean in the west to the Gulf of Mexico in the east. The border traver ...

into the state of

Baja California Baja California (; 'Lower California'), officially the Free and Sovereign State of Baja California ( es, Estado Libre y Soberano de Baja California), is a state in Mexico. It is the northernmost and westernmost of the 32 federal entities of Mex ...

, Mexico. The northwestern end of the trough starts at the

San Gorgonio Pass The San Gorgonio Pass, or Banning Pass, is a elevation gap on the rim of the Great Basin between the San Bernardino Mountains to the north and the San Jacinto Mountains to the south. The pass was formed by the San Andreas Fault, a major tran ...

in Riverside County, and extends southeast to the Gulf of California. Major geographical features located in the trough include the

Coachella Valley , map_image = Wpdms shdrlfi020l coachella valley.jpg , map_caption = Coachella Valley , location = California, United States , coordinates = , width = , boundaries = Salton Sea (southeast), Santa Rosa Mountains (southwest), San Jacint ...

, the

Salton Sea The Salton Sea is a shallow, landlocked, highly saline body of water in Riverside and Imperial counties at the southern end of the U.S. state of California. It lies on the San Andreas Fault within the Salton Trough that stretches to the Gulf ...

, and the

Imperial Valley , photo = Salton Sea from Space.jpg , photo_caption = The Imperial Valley below the Salton Sea. The US-Mexican border runs diagonally across the lower left of the image. , map_image = Newriverwatershed-1-.jpg , map_caption = Map of Imperial ...

, in the United States, and the western side of the

Mexicali Valley Mexicali (; ) is the capital city of the Mexican state of Baja California. The city, seat of the Mexicali Municipality, has a population of 689,775, according to the 2010 census, while the Calexico–Mexicali metropolitan area is home to 1,000,0 ...

, and the

Colorado River Delta The Colorado River Delta is the region where the Colorado River flows into the Gulf of California (also known as the Sea of Cortez) in eastern Mexicali Municipality in the north of the state of Baja California in northwesternmost Mexico. The ...

in Mexico. The Salton Trough is a result of crustal stretching and sinking caused by the combined actions of the

San Andreas Fault The San Andreas Fault is a continental transform fault that extends roughly through California. It forms the tectonic boundary between the Pacific Plate and the North American Plate, and its motion is right-lateral strike-slip (horizontal). ...

and the East Pacific Rise, particularly the Gulf of California Rift Zone (GCRZ), the northernmost portion of the East Pacific Rise. The GCRZ and the San Andreas Fault both terminate near the south end of the Salton Sea, in an area called the

Brawley Seismic Zone The Brawley Seismic Zone (BSZ), also known as the Brawley fault zone, is a predominantly extensional tectonic zone that connects the southern terminus of the San Andreas Fault with the Imperial Fault in Southern California. The BSZ is named for ...

. The Brawley seismic zone is an active spreading center that connects the San Andreas Fault system with the

Imperial Fault Zone The Imperial Fault Zone is a system of geological faults located in Imperial County in the Southern California region, and adjacent Baja California state in Mexico. It cuts across the border between the United States and Mexico. Geology The ...

to the south. The Salton Trough is also referred to as a sedimentary basin because the basin has filled with sedimentary deposits as quickly as the basin has been sinking. In some areas, the sediment is more than deep. Sources of the sediment are the mountainous areas that surround the trough, and the

Colorado River The Colorado River ( es, Río Colorado) is one of the principal rivers (along with the Rio Grande) in the Southwestern United States and northern Mexico. The river drains an expansive, arid watershed that encompasses parts of seven U.S. sta ...

, which in the past fed Lake Cahuilla, a large inland freshwater lake, that disappeared after the Colorado River changed course to the Gulf of California.

Facts about the Salton Trough

*At below sea level, the

Salton Sink The Salton Sink is the low point of an endorheic basin, a closed drainage system with no outflows to other bodies of water, in the Colorado Desert sub-region of the Sonoran Desert. The sink falls within the larger Salton Trough and separates th ...

is the topographic low area within the Salton Trough, and is the second-lowest point, after

Death Valley Death Valley is a desert valley in Eastern California, in the northern Mojave Desert, bordering the Great Basin Desert. During summer, it is the hottest place on Earth. Death Valley's Badwater Basin is the point of lowest elevation in Nort ...

, on the North American continent. At the

, which fills the lowest part of the Salton Sink, is the lowest lake in North America. *The Salton Trough is commonly subject to migrating earthquake swarms. *The

Salton Buttes The Salton Buttes are a group of volcanoes in California, on the Salton Sea. They consist of a -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 ...

, located within the Salton Sea, are

rhyolite Rhyolite ( ) is the most silica-rich of volcanic rocks. It is generally glassy or fine-grained (aphanitic) in texture, but may be porphyritic, containing larger mineral crystals ( phenocrysts) in an otherwise fine-grained groundmass. The miner ...

lava domes within the basin which were active 10,300 (± 1000) years BP. *Within the field of

Physical Geography Physical geography (also known as physiography) is one of the three main branches of geography. Physical geography is the branch of natural science which deals with the processes and patterns in the natural environment such as the atmosphere, ...

the Salton Trough is classified as a distinct section of the

Basin and Range province The Basin and Range Province is a vast physiographic region covering much of the inland Western United States and northwestern Mexico. It is defined by unique basin and range topography, characterized by abrupt changes in elevation, alternating ...

within the Intermontane Plateaus division of the American Landmass. * The

Niland Geyser Niland Geyser (nicknamed the "Slow One" and formally designated W9) is a moving mud pot or mud spring outside Niland, California in the Salton Trough in an area of geological instability due to the San Andreas fault, formed due to carbon dioxide b ...

is one of dozens of mud pots and mud volcanoes in the Salton Trough, but is the only one in the world known to have moved significantly, affecting the Union Pacific Railroad,

California State Route 111 State Route 111 (SR 111) is a state highway in the U.S. state of California. It is the main north-south route and retail corridor through the Coachella Valley, a part of the Colorado Desert in the southeastern corner of the state and a famous res ...

, and other infrastructure since 2018.

References

Pull-apart basins Colorado Desert Geologic provinces of California Geology of Imperial County, California Geology of Riverside County, California Geology of San Diego County, California Geological depressions in the United States Physiographic sections Physiographic regions of the United States *Trough Geography of Baja California {{US-geology-stub