SONOMA, Calif. (AP) - An earthquake with a preliminary magnitude of 6.0 struck California's northern San Francisco Bay area early Sunday, the U.S. Geological Survey said.
The earthquake struck just before 3:30 a.m. about 10 miles northwest of American Canyon, which is about 6 miles southwest of Napa, in California wine country, Leslie Gordon of the U.S. Geological Survey said.
It's the largest earthquake to shake the Bay Area since the 6.9 magnitude Loma Prieta quake in 1989, the USGS said.
The shaking set off car alarms and had residents of neighboring Sonoma County running out of their houses in the middle of night. Officials say widespread power outages have been report in Sonoma County.
A member of Napa County dispatch tells The Associated Press that there has been one report of structural damage, but additional details weren't immediately available.
"It was a rolling quake, said Oakland resident Rich Lieberman. "It started very much like a rolling sensation and just got progressively worse in terms of length. Not so much in terms of shaking, but it did shake. It felt like a side-to-side kind of rolling sensation. Nothing violent but extremely lengthy and extremely active."
The USGS says the depth of the earthquake was just less than seven miles, and numerous small aftershocks have occurred in the Napa wine country.
"A quake of that size in a populated area is of course widely felt throughout that region," said Randy Baldwin, a geophysicist with the U.S. Geological Survey in Golden, Colorado, "The 6.0 is a sizeable quake for this area. It's a shallow quake. It's about 6 miles deep. We received hundreds of reports on our website from people that felt it in the surrounding area."
There was no immediate report of injuries.