San Andreas Fault, California (CA), United States

Facts & Statistics
Place Name	San Andreas Fault
Place Status (Type)	geological feature
Location	San Mateo County, California (CA), United States, North America
Latitude	unknown
Longitude	unknown

San Andreas Fault , large rift in the earth's crust in coastal Calif. It is the principal fault of an intricate network of faults extending more than 600 mi/966 km from NW Calif. to the Gulf of California. The San Andreas fault, a strike-slip fault, also extends vertically at least 20 mi/32 km into the earth. It is located on the boundary bet. 2 sects. of the earth's crust—the N. Amer. plate and the Pacific plate—and separates SW Calif. from remainder of the N. Amer. continent. The Pacific plate is moving NW in relation to the N. Amer. plate, and it is believed that the total displacement along the fault since its formation more than 30 million years ago has been about 350 mi/563 km. Movement along the fault causes earthquakes; several thousand occur annually, although only a few are of moderate or higher magnitude. The destructive San Francisco earthquake of 1906 was caused by a movement in which land surfaces on either side of the fault were displaced horizontally up to 21 ft/6 m. The rift is most noticeable on surface at Upper and Lower Crystal Springs reservoirs and San Andreas Reservoir, in San Mateo co., S of San Francisco; the reservoirs are aligned SE-NW with the fault. It continues NW beneath Pacific Ocean and reemerges at Point Reyes Peninsula, Monterey co., where it nearly separates peninsula from mainland.