An earthquake shook the San Francisco Bay Area a short time ago, rattling nerves and buildings from San Jose to northern Marin County but causing no reported damage or injuries.
The United States Geological Survey said the quake, which had a preliminary magnitude of 5.2, was centered about three miles southwest of the town of Gilroy, about 75 miles southeast of San Francisco - an area bisected by the San Andreas Fault.
Gilroy Mayor Mr Tom Springer told Reutersthere were reports of broken glass and fire sprinklers going off, but no reports of serious damage.
"It was a good shaking, and I guess we were right on top of it," Mr Springer told Reuters. "Fire crews are out, police are out, but we have not seen many problems and had zero calls for medical emergencies."
Residents of cities from San Jose to Oakland said they felt a sharp rolling motion, rattling windows in their frames and causing power lines to swing violently.
In San Francisco, officials briefly halted the BART rapid transit system and commuter trains to check tracks for possible quake damage.
Ms Julie Martinez, a geophysicist at the USGS National Earthquake Center in Golden, Colorado, said the quake was officially classified as a moderate temblor but, in an area with strict building codes such as California, unlikely to cause much damage.
San Francisco's last major destructive quake was the 1989 Loma Prieta earthquake, a 7.1 tremor that killed 67 people and caused widespread damage, including bringing down part of the Oakland-San Francisco Bay Bridge.