San Andreas Fault

The San Andreas Fault is a transform fault, where the Pacific Plate drifts over on the North American plate. It covers about 1100 km length of Mexico to the north of San Francisco and the state of California is divided into two halves, with San Francisco are located on the North American plate and Los Angeles on the Pacific plate. The profound rejection was named after the San Andreas Lake, which is located south of San Francisco and the water-filled San Andreas Fault is. Otherwise, they can not be seen on long drives with the naked eye in the landscape and therefore marked with piles. April 18, 1906 was here, however, a clear line of fracture; on this day was San Francisco by a severe earthquake measuring 7.8 on the moment magnitude scale, called the San Francisco earthquake of 1906 struck. The San Andreas Fault is one of the few plate boundaries on land; the vast number of plate boundaries lies at the bottom of the oceans.

Movement

The annual shift of the earth's crust to each other can be determined on the basis of decreasing plate distance between Los Angeles and San Francisco. Accordingly, it is about 6 inches per year. The North American Plate to the south, and the Pacific pushes opposite.

The motion will be located here but not the same everywhere constant; some areas of the fault move almost constantly, while snag other areas and only occasionally jerky to move to the part of several meters against each other -. up to six feet at the San Francisco earthquake of 1906 At Fort Tejon earthquake of 1857 to the shift sometimes have even reach up to nine meters.

Geologists are of the opinion that for at least 31 million years, the San Andreas Fault system must be in motion. During this time, the Reyes Peninsula has shifted from the south by 450 km to its present location. The two pinnacles originated about 23 million years in the same place. In the meantime, however, they were offset along the San Andreas Fault by 313 km. The Northern Pinnacles are therefore 313 km from its origin, today's Neenach formation away. And still much does the system of the San Andreas Fault: A few hundred thousand years, Point Reyes will be an island that is " run over " on their way to Alaska to Bodega Bay. Only in the late 1960s, scientists discovered that the San Andreas Fault is the boundary between two tectonic plates and earthquakes therefore are inevitable. Since this time, for the people in the region no longer the question of if but when it will come to the next earthquake. Since 1984, the U.S. federal agency United States Geological Survey carries out intensive investigations, particularly in located directly on the San Andreas Fault town of Parkfield. They should help to improve the predictive capabilities of earthquakes. An attempt is made since 2004 with the help of SAFOD (San Andreas Fault Observatory at Depth) for the first time to drill a deep borehole directly with an active plate boundary, in order to directly draw conclusions about the processes in the fault during an earthquake can.

Course

The San Andreas Fault is divided by geologists into three sections:

• The southern segment begins near the Salto lake and is named after the adjacent Mojave Desert as Mojave segment. Here, the fault runs first north before it swings in the course to the northwest and meets only on the San Bernardino Mountains to the north and finally to the San Gabriel Mountains in the south. ( These mountain ranges arose due to the rubbing together of two continental plates ).
• The central segment runs ( also north-west ), between Parkfield and Hollister.
• The northern segment of the San Andreas fault runs from Hollister on the San Francisco peninsula and extends from there - under water - to Cape Mendocino, on which finally meet three continental plates to each other.