More than 8,000 residents reported shaking from the earthquake. San Francisco is some 60 miles north of the quake's epicenter.
A light earthquake hit the southern San Francisco Bay area Friday afternoon, triggering a few false fire alarms but causing no significant damage.
The magnitude 4.1 quake occurred along the Calaveras fault, with an epicenter located 13 miles east southeast of San Jose in the San Felipe Hills.
The Calaveras fault is one of several that slice through the bay area and are capable of damaging earthquakes. These faults are related to the region's granddaddy, the San Andreas fault, which marks the boundary between two large, moving patches of Earth's crust – the Pacific and North American plates.
The quake struck at 4:10 p.m. Pacific time. Slightly more than 8,000 residents in the region, including people in San Francisco, which is some 60 miles north of the quake's epicenter, reported shaking to the US Geological Survey's "Did You Feel It?" website.
"Everything just rolled and jiggled in our office," said Petra Albrecht, a coroner investigator for the Santa Clara County Medical Examiner-Coroner's Office, in an interview with the San Jose Mercury News.