A magnitude 5.6 earthquake struck in a rural area about 9 miles northeast of San Jose, California, Silicon Valley's biggest city, last night, causing minor damage.
The earthquake was felt across the San Francisco Bay Area and beyond just before 8:05pm (local time).
There were no immediate reports of major damage but the San Jose Mercury News Web site reported phone service failed in a part of Palo Alto, home to Hewlett-Packard computer company and Stanford University.
It said the quake caused minor damage and residents poured out of apartments in downtown San Jose to survey the damage. San Jose in the 10th most populous US city.
"It was pretty significant. you could actually hear the rumbling of the ground. It was a good shake," said Nick Muyo, a spokesman for the San Jose Police Department.
Asked about damage, he said he knew of "nothing other than things tipping off cabinets and dressers."
The US Geological Survey said the quake occurred on the Calaveras Fault, located east of the San Andreas Fault along which some of the most destructive earthquakes in California have struck -- including one in 1906 which, together with a subsequent fire, destroyed much of San Francisco.
Residents of San Francisco, 50 miles north of San Jose, and Stockton, the same distance to the east, reported feeling Tuesday's quake.
Jeff Brown, a spokesman for video game publisher Electronic Arts Inc based in Redwood Shores, 25 miles north of San Jose, said: "There's no damage but a couple people are there and they said the curtains banged against the windows and the building creaked. They definitely felt it."