The San Andreas Fault is a continental right-lateral strike-slip transform fault that extends roughly 1,200 kilometers (750 mi) through the U.S. state of California. It forms part of the tectonic boundary between the Pacific Plate and … See more

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 L… See more

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. … See more

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 … See more

The fault was first identified in Northern California by UC Berkeley geology professor Andrew Lawson in 1895 and named by him after the surrounding San Andreas valley. Eleven years later, Lawson discovered … See more