SAN FRANCISCO -- New evidence suggests the 1906 earthquake ruptured the San Andreas Fault in a single trace through Portola Village, current day Town of Portola Valley, and indicates a revised location for the fault trace.
Portola Valley, south of San Francisco, has been extensively studied and the subject of the first geological map published in California. Yet studies have offered conflicting conclusions, caused in part by a misprinted photograph and unpublished data, as to the location and nature of the 1906 surface rupture through the area.