Full Answer
Where is the fault line in California?
Among other sites, the fault runs directly under the now-abandoned old city hall in downtown Hayward, the University of California-Berkeley football stadium, the Mira Vista Golf Course near Berkeley, Lake Temescal, Contra Costa College, and Port Pinole Shoreline Regional Park. The three decades mentioned earlier may be an optimistic time span.
What is the California Geological Survey's Interactive Fault map?
The California Geological Survey's interactive map allows users to identify the location and classification of faults throughout California. Information available includes the age of the most recent activity on each fault segment, surface rupture areas, and whether or not the faults are visible at the surface.
What is the San Andreas Fault System in California?
The San Andreas fault system is the major geologic boundary between the North American and Pacific tectonic plates and passes through much of the state. It will create the biggest earthquakes—as big as magnitude 8—that will disrupt the whole region. But smaller magnitude earthquakes can also cause damaging levels of ground shaking.
What fault line is California on?
The San Andreas Fault SystemThe San Andreas Fault System, which crosses California from the Salton Sea in the south to Cape Mendocino in the north, is the boundary between the Pacific Plate (that includes the Pacific Ocean) and North American Plate (that includes North America).
What is under the San Andreas Fault?
The San Andreas runs deep near and under some of California's most populated areas. The cities of Desert Hot Springs, San Bernardino, Wrightwood, Palmdale, Gorman, Frazier Park, Daly City, Point Reyes Station and Bodega Bay rest on the San Andreas fault line.
What is the most famous fault line?
The San Andreas FaultThe San Andreas Fault is the most famous fault in the world. Its notoriety comes partly from the disastrous 1906 San Francisco earthquake, but rather more importantly because it passes through California, a highly-populated state that is frequently in the news.
Will the San Andreas Fault destroy California?
Interstates 10 and 15 both cross the San Andreas fault and could become impassable, cutting off Southern California from population centers in Las Vegas and Phoenix. The aqueducts that bring in 88% of Los Angeles' water and cross the San Andreas fault could be damaged or destroyed, Jones has told The Times.
How far away from faults do most Californians live?
Most Californians live within 30 miles of an active fault. 15,700. Known faults in California (and scientists continue to discover new ones) Select your county from the dropdown menu above to learn more about California earthquake risk and faults near you. *The probability is based on a 30-year period, beginning in 2014.
What would happen if a large earthquake hit the coast?
Very large earthquakes occurring close to the coast could cause damaging levels of ground shaking and tsunami waves.
How were the mountains and valleys formed?
Many of the mountains, and some of the valleys, in Southern California were formed by movement within the San Andreas fault system —the tectonic boundary between the Pacific and North American tectonic plates.
What fault is the longest in California?
The San Andreas fault is the primary feature of the system and the longest fault in California, slicing through Los Angeles County along the north side of the San Gabriel Mountains. It can cause powerful earthquakes—as big as magnitude 8.
Which fault system is the major boundary between the North American and Pacific tectonic plates?
The greater San Francisco Bay Area has a high likelihood of future damaging earthquakes as it straddles the San Andreas fault system —the major geologic boundary between the North American and Pacific tectonic plates.
What is the Cascadia subduction zone?
The Cascadia Subduction Zone stretches underneath the Humboldt-Del Norte county region, extending from Cape Mendocino all the way up through the Pacific Northwest. This zone is capable of generating an earthquake of a magnitude 9 or larger, occurring—on average—once every 500 years.
What is the landscape of Southern California?
Inland Southern California has scenic mountains, valleys, and deserts. Tremendous geologic forces within the San Andreas fault system —the tectonic boundary between the Pacific and North American tectonic plates—created this spectacular landscape and continue today, reminding us often that we live in earthquake country.
Why is Parkfield important?
Due to the frequency of predictable activity, Parkfield has become one of the most important areas in the world for large earthquake research. In 2004, work began just north of Parkfield on the San Andreas Fault Observatory at Depth (SAFOD).
How many segments does the San Andreas fault have?
The fault divides into three segments, each with different characteristics and a different degree of earthquake risk. The slip rate along the fault ranges from 20 to 35 mm (0.79 to 1.38 in)/yr. It was formed by a transform boundary.
How long has the San Andreas fault been around?
The main southern section of the San Andreas Fault proper has only existed for about 5 million years.
How long will the San Andreas fault slide past San Francisco?
Assuming the plate boundary does not change as hypothesized, projected motion indicates that the landmass west of the San Andreas Fault, including Los Angeles, will eventually slide past San Francisco, then continue northwestward toward the Aleutian Trench, over a period of perhaps twenty million years.
What is the name of the mountain range that runs through the San Andreas fault?
These mountains are a result of movement along the San Andreas Fault and are commonly called the Transverse Range.
What plate is the San Andreas fault?
A continental transform fault through California between the Pacific Plate and the North American Plate. This article is about the continental fault in California. For other uses, see San Andreas (disambiguation). San Andreas Fault. The fault, right, and the Carrizo Plain, left.
What was the magnitude of the San Francisco earthquake in 1957?
1957 San Francisco earthquake: A magnitude 5.7 quake with an epicenter on the San Andreas fault in the ocean west of San Francisco and Daly City.
Which fault system provides evidence for active northeastward tilting of the Santa Rosa Mountains and southern California?
The southern San Andreas fault system (California, USA ) provides an excellent natural laboratory for studying the controls on vertical crustal motions related to strike-slip deformation. Here we present geologic, geomorphic, and gravity data that provide evidence for active northeastward tilting of the Santa Rosa Mountains and southern Coachella...
What is the San Andreas fault?
The San Andreas fault ( SAF) is one of the most studied strike‐slip faults in the world; yet its subsurface geometry is still uncertain in most locations. The Salton Seismic Imaging Project (SSIP) was undertaken to image the structure surrounding the SAF and also its subsurface geometry. We present SSIP studies at two locations in the Coachella...
What is the name of the mountain that drains the San Bernardino Mountains?
Photograph from summit of San Jacinto Peak looking north across San Gorgonio Pass toward San Gorgonio Mountain. San Gorgonio River and Interstate Highway 10 traverse the Pass lowland; the Whitewater River drains the San Bernardino Mountains and flows eastward into the Salton Trough. San Gorgonio Pass is known as a geologically complex segment of the San Andreas Fault that traverses the landscape from southeast to northwest (white arrows mark the approximate trace of one of the multiple fault lines in the Pass region).
What is the evolution of Southern California?
The geologic and landscape evolution of southern California is framed by plate tectonic interactions between the North America and Pacific plates, leading most recently to the growth of the San Andreas Fault system. Our project studies are helping to document the evolving formation and deformation of crustal blocks—accompanied by the growth and subsequent disruption of mountain ranges and flanking basins—that record the magnitude, timing, and interactive roles of faults comprising this plate-margin system.
What fault is Mill Creek?
The fault history of the Mill Creek strand of the San Andreas fault (SAF) in the San Gorgonio Pass region, along with the reconstructed geomorphology surrounding this fault strand, reveals the important role of the left-lateral Pinto Mountain fault in the regional fault strand switching.
How many people live in Southern California?
Southern California is home to nearly 24 million people and countless visitors who live, recreate, consume resources, and face the risk of natural hazards in the region. This project produces high-quality, multi-purpose geologic maps, databases, and reports that portray our understanding of the region’s four-dimensional geologic framework. We conduct stratigraphic, structural, geomorphological, geophysical, geochronological, and paleontological studies, and we assist other stakeholders in applying our findings toward establishing geologic context for diverse land-use management issues; for assessing water, mineral, and energy resources; and for understanding natural hazards.
How does plate margin deformation lead to natural hazards?
Plate-margin deformation leads either directly (through seismic events) or indirectly (by creating steep range-front relief) to high-risk of natural hazards in southern California, home to more than 24 million people.
Overview
The San Andreas Fault is a continental transform fault that extends roughly 1,200 kilometers (750 mi) 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). The fault divides into three segments, each with different characteristics and a different degree of earthquake risk. The slip rate along th…
Fault zones
The northern segment of the fault runs from Hollister, through the Santa Cruz Mountains, epicenter of the 1989 Loma Prieta earthquake, then up the San Francisco Peninsula, where it was first identified by Professor Lawson in 1895, then offshore at Daly City near Mussel Rock. This is the approximate location of the epicenter of the 1906 San Francisco earthquake. The fault returns onshore at Bolinas …
Plate boundaries
The Pacific Plate, to the west of the fault, is moving in a northwest direction while the North American Plate to the east is moving toward the southwest, but relatively southeast under the influence of plate tectonics. The rate of slippage averages about 33 to 37 millimeters (1.3 to 1.5 in) a year across California.
The southwestward motion of the North American Plate towards the Pacific is creating compres…
Formation
The San Andreas began to form in the mid Cenozoic about 30 Mya (million years ago). At this time, a spreading center between the Pacific Plate and the Farallon Plate (which is now mostly subducted, with remnants including the Juan de Fuca Plate, Rivera Plate, Cocos Plate, and the Nazca Plate) was beginning to reach the subduction zone off the western coast of North America. As the relative motio…
Study
The fault was first identified in Northern California by UC Berkeley geology professor Andrew Lawson in 1895 and named by him after the Laguna de San Andreas, a small lake which lies in a linear valley formed by the fault just south of San Francisco. Eleven years later, Lawson discovered that the San Andreas Fault stretched southward into southern California after reviewing the effects …
Earthquakes
The San Andreas Fault has had some notable earthquakes in historic times:
• 1857 Fort Tejon earthquake: About 350 kilometers (220 mi) were ruptured in central and southern California. Though it is known as the Fort Tejon earthquake, the epicenter is thought to have been located far to the north, just south of Parkfield. Two deaths were reported. Its moment magnitude was 7.9.
See also
• California earthquake forecast
• Central Valley (California) – Flat valley that dominates central California
• Coast Range Geomorphic Province
• Garlock Fault – Fault running along the margins of the Mojave Desert of Southern California,United States
Further reading
• Collier, Michael (December 1, 1999). A Land in Motion. UC Press. ISBN 978-0-520-21897-0.
• Stoffer, Philip W. (2005). The San Andreas Fault In The San Francisco Bay Area, California: A Geology Fieldtrip Guidebook To Selected Stops On Public Lands. USGS. General Interest Publication 16.