San Andreas Fault

The San Andreas Fault is a roughly 750-mile right-lateral transform fault that forms a major part of the boundary between the Pacific and North American plates, whose slow motion past each other makes it one of California’s greatest earthquake hazards. It began forming about 30 million years ago, with the modern southern section taking shape about 5 million years ago. Identified in 1895 by Andrew Lawson and linked by him to the 1906 San Francisco earthquake, it later helped establish the reality of hundreds of miles of lateral movement. Divided into northern, central, and southern segments, it also shapes California’s landscape and remains a major focus of earthquake research and risk planning.

Fellows, California · United States