Historical Background
- The fault is believed to have formed over 28 million years ago in the mid-Cenozoic era.
- It is believed to have begun when the East Pacific Rise subducted underneath the North American Plate. ...
- In 1895, Professor Andrew Lawson discovered the northern zone of the fault and named it the San Andreas fault. ...
How many people died from the San Andreas Fault?
Nov 30, 2016 · Scientists have learned that the Earth's crust is fractured into a series of "plates" that have been moving very slowly over the Earth's surface for millions of years. Two of these moving plates meet in western California; the boundary between them is the San Andreas fault.
Why is the San Andreas Fault a transform boundary?
Jun 07, 2020 · How did the San Andreas Fault form? The San Andreas Fault was born about 30 million years ago in California, when the Pacific Plate and the North America plate first met. The new configuration meant the two plates slid past one another instead of crashing into each other, a boundary called a strike-slip fault. Click to see full answer.
How you can find and see the San Andreas Fault?
Jan 18, 2012 · The San Andreas Fault forms an active tectonic plate boundary, and as such, one would expect uplift and landscape evolution in the Coast Ranges to be closely tied to fault displacement. Such an interpretation would imply that landscape could be as old as 29 million years. Instead, the evidence suggests that landscape is considerably younger.
What caused the San Andreas Fault?
The San Andreas Fault received its name from Andrew Lawson after the 1906 earthquake. He named it for San Andreas Lake, a (now) man-modified sag pond in San Mateo county through which the fault passes. The lake was named by Gaspar de Portola in 1769 who camped near the (then) small body of water (See etymology link below).
When did the San Andreas Fault form?
The San Andreas Fault was born about 30 million years ago in California, when the Pacific Plate and the North America plate first met. Before then, another oceanic plate, the Farallon plate, was disappearing beneath North America at a subduction zone, another type of plate boundary.Mar 10, 2015
What boundary formed the San Andreas Fault?
transformAccording to the theory of plate tectonics, the San Andreas Fault represents the transform (strike-slip) boundary between two major plates of the Earth's crust: the Northern Pacific to the south and west and the North American to the north and east.
How did the San Andreas Fault form for kids?
The Northern Pacific plate is sliding laterally past the North American plate in a northerly direction, and hence the San Andreas is classified as a strike-slip fault.
How was the San Andreas Fault formed quizlet?
Birth of the San Andreas Fault. The Pacific Plate came in contact with the North American Plate and formed a strike slip boundary. This contact happened after the subduction of the Farallon plate.
Where does San Andreas Fault start?
the Salton SeaThe San Andreas Fault begins near the Salton Sea, runs north along the San Bernardino Mountains, crosses Cajon Pass, and then runs along the San Gabriel Mountains east of Los Angeles.May 7, 2020
How do faults produce earthquake?
Earthquakes are the result of sudden movement along faults within the Earth. The movement releases stored-up 'elastic strain' energy in the form of seismic waves, which propagate through the Earth and cause the ground surface to shake.
What is the San Andreas Fault easy explanation?
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).
Is the San Andreas Fault an earthquake zone?
This region has a long history of damaging earthquakes. Large earthquakes will occur along the San Andreas fault system—the major geologic boundary between the North American and Pacific tectonic plates—which passes through much of the State of California.
Why is the San Andreas Fault so popular?
The 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.
What is the San Andreas Fault quizlet?
What is the San Andreas Fault? A transform boundary. 810 miles of transform boundary in California. Where the North American Plate and Pacific Plate slide past each other.
What type of fault is the San Andreas Fault quizlet?
What is the San Andreas Fault? A 1300km conservative plate boundary in California, where the North American Plate (slower rate of 1cm per year) and Pacific Plate (moving in the same direction but at a faster rate) slide past each other. A Strike-Slip Fault Displacement is lateral along fault.
What type of plate boundary includes the San Andreas Fault quizlet?
The San Andreas Fault is the boundary between two of Earth's tectonic plates: the Pacific Plate and the North American Plate. This boundary is a transform boundary.
Where was the San Andreas fault located?
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.
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.
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.
Where is Box Canyon?
Box Canyon, near the Salton Sea, contains upturned strata associated with that section of the fault. The fault then runs along the southern base of the San Bernardino Mountains, crosses through the Ca jon Pass and continues northwest along the northern base of the San Gabriel Mountains.
Who discovered the San Andreas fault?
Eleven years later, Lawson discovered that the San Andreas Fault stretched southward into southern California after reviewing the effects of the 1906 San Francisco earthquake. Large-scale (hundreds of miles) lateral movement along the fault was first proposed in a 1953 paper by geologists Mason Hill and Thomas Dibblee.
How often does the San Andreas fault cause earthquakes?
Seismologists discovered that the San Andreas Fault near Parkfield in central California consistently produces a magnitude 6.0 earthquake approximately once every 22 years. Following recorded seismic events in 1857, 1881, 1901, 1922, 1934, and 1966, scientists predicted that another earthquake should occur in Parkfield in 1993. It eventually occurred in 2004. Due to the frequency of predictable activity, Parkfield has become one of the most important areas in the world for large earthquake research.
How many people died in the San Francisco earthquake?
The epicenter was near San Francisco. At least 3,000 people died in the earthquake and subsequent fires. The magnitude was estimated to be 7.8. 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.
What is the San Andreas fault?
The San Andreas Fault System. The San Andreas Fault is one of the most intensely studied faults on the planet. It is a continental transform that separates the Pacific plate from the North American plate along its entire trace. The trace of the fault through California is shown in Figure 17.1.
What is the Parkfield section of the San Andreas fault?
The Parkfield section of the San Andreas fault (SAF) is an ideal segment for the peculiar aspects of fault rheology, characterized by a progressive decrease in creep rate and slip mode change. The intense multidisciplinary investigations carried out in past decades make this fault segment the most investigated so far in the world. Consequently, numerous tomographic models have been published using different datasets and techniques that all agree with some heterogeneities of the fault structure (i.e., Thurber et al., 2004 ).
Is the San Andreas fault continuous?
As with the Wasatch Fault in Utah, and with any large fault, the surface trace of the San Andreas is not continuous. Instead, the surface trace is segmented such that individual fault segments may act independently of one another. One or several segments may break during an earthquake.
How old is the San Andreas fault?
The San Andreas fault is about 28 million years old. Back then, California didn't exist, at least not recognizably so. Bits and pieces could be found scattered around the western edge of North American, which at the time ended at the Pacific ocean lapping the shores of central Utah and Arizona. Other parts were volcanic islands in ...
What did Wegener discover?
Though trained as an astronomer and working as a meteorologist, Wegener visited the Atlantic shores and found that rocks and fossils on one side of the ocean matchedthose on the other side . Wegener proposed that the continents were drifting apart. He was roundly damned by geologists as an outsider and ignored.
Who discovered the San Andreas fault?
The fault was first identified in 1895 by professor Andrew Lawson from UC Berkeley who discovered the northern zone. It is named after San Andreas Lake, a small body of water that was formed in a valley between the two plates. Following the 1906 San Francisco earthquake, Lawson concluded that the fault extended all the way into southern California.
How far is the San Andreas fault?
The San Andreas Fault is a continental transform fault that extends roughly 1300 km (810 miles) 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 ...
Overview
- The San Andreas fault was formed by the movement of the North American and Pacific tectonic plates sliding past each other in opposite directions. This movement causes displacement of objects on each side of the fault as stress from the movement builds up.
Formation
Fault zones
Plate boundaries
Study
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…
Earthquakes
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 …
See also
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…
Further reading
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 …