The Imperial Fault Zone is a system of

geological Geology () is a branch of natural science concerned with Earth and other astronomical objects, the features or rocks of which it is composed, and the processes by which they change over time. Modern geology significantly overlaps all other E ...

faults located in

Imperial County Imperial Count (german: Reichsgraf) was a title in the Holy Roman Empire. In the medieval era, it was used exclusively to designate the holder of an imperial county, that is, a fief held directly ( immediately) from the emperor, rather than from ...

in the

Southern California Southern California (commonly shortened to SoCal) 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 a ...

region, and adjacent

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 ...

state in Mexico. It cuts across the border between the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territori ...

and

Mexico Mexico (Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatema ...

Geology

The Imperial Fault Zone is a right lateral-moving strike-slip fault, representing the northernmost transform fault associated with the

East Pacific Rise The East Pacific Rise is a mid-ocean rise (termed an oceanic rise and not a mid-ocean ridge due to its higher rate of spreading that results in less elevation increase and more regular terrain), a divergent tectonic plate boundary located alon ...

. It is connected to 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 (horizonta ...

by the Brawley Seismic Zone. It terminates on its southern end at the

Cerro Prieto Cerro Prieto ( coc, Wee Ñaay, eng, "Black Hill") is a volcano located approximately 29 km (18 mi) SSE of Mexicali in the Mexican state of Baja California. The volcano lies astride a spreading center associated with the East Pacific R ...

spreading center. The Imperial Fault Zone is thought to accommodate slip from both the San Andreas and the San Jacinto fault zones. However, studies covering the last few hundred years show that the slip rate is insufficient to account for the total slip from the San Andreas system.Treiman, J.Jerome, compiler, 1999, Fault number 132, Imperial fault, in Quaternary fault and fold database of the United States: U.S. Geological Survey website, http://earthquakes.usgs.gov/hazards/qfaults The surface trace is well-located based on mapped surface offsets from historic events.

Earthquake history

The Imperial Fault Zone has a history of earthquakes of moderate magnitude, including several

doublet earthquake __NOTOC__ In seismology, doublet earthquakes – and more generally, multiplet earthquakes – were originally identified as multiple earthquakes with nearly identical waveforms originating from the same location. They are now characterized as sin ...

s. * 1915 Imperial Valley earthquakes: Two

magnitude Magnitude may refer to: Mathematics *Euclidean vector, a quantity defined by both its magnitude and its direction *Magnitude (mathematics), the relative size of an object *Norm (mathematics), a term for the size or length of a vector *Order of ...

6.25 shocks occurred ~1 hour apart. Six people died and several were injured in the second quake at

Mexicali 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 ...

, located just inside the Mexican border. Unstable banks of the New and Alamo Rivers caved in many places. * 1940 El Centro earthquake * 1979 Imperial Valley earthquake * 2010 Baja California earthquake

References

External links

Southern California Earthquake Data Center website: Imperial Fault Zone
{{- Seismic faults of California Seismic faults of Mexico Strike-slip faults Geology of Imperial County, California Natural history of Baja California Natural history of the Colorado Desert El Centro metropolitan area Imperial Valley Salton Trough

Geology

Earthquake history

See also

References

Further reading

External links