Published: Aug 24, 2014 8:35 AM EDT
Updated: Aug 24, 2014 11:39 AM EDT

SONOMA, Calif.- Officials say an earthquake with a preliminary magnitude of 6.0 has been reported in California's northern San Francisco Bay area.
Leslie Gordon of the U.S. Geological Survey says it struck at just before 3:30 a.m. Sunday about 10 miles northwest of American Canyon, which is about six miles southwest of Napa. The USGS says it's the largest earthquake to shake the Bay Area since the 1989 6.9 magnitude Loma Prieta quake.
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.
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 member of Napa County dispatch tells The Associated Press that there has been one report of structural damage, but additional details were not available.
There was no immediate report of injuries.

Mary and Tim Briggs are visiting Napa Valley from southwest Florida.They were woken up by the intense shaking. "The clock said about 3:15," Mary Briggs said. "We were sound asleep and then the bed just started shaking violently. It really kind of like it was levitating and shaking and things started falling off the walls and falling off the tables. It only lasted 15-20 seconds but it was incredibly scary. All the chairs fell over, all the wine bottles and their glassware, decor just smashed all over the lobby."

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