The earthquake was recorded about 2 miles east of Oakland and had a preliminary magnitude of 4.2, according to the U.S. Geological Survey. The quake, which struck at about 4:40 a.m., was felt on both sides of the San Francisco Bay and was reported as lasting up to 10 seconds.

The tremor shattered glass in Berkeley, breaking windows at a Safeway store that was closed because of the damage. It also left a big hole in the window of Dream Fluff Donuts, a neighborhood institution in the Elmwood district about a mile from the University of California, Berkeley campus.

The damage meant rows of glistening doughnuts in the front window of the Dream Fluff weren't for sale Friday, but that didn't put much of a cramp in business with the usual bustle of customers stopping by for coffee and other freshly baked goods.

Many compared notes on the early morning excitement.

"I sat bolt upright in bed," said neighborhood resident Hank Williams, who had a few pictures fall off walls. Something fell in front of his cat, "who was out the cat door and gone. The cat has left town," he said.

A property manager, Williams made the rounds checking for the smell of gas, but said there didn't seem to be any serious problems.

Ken McKee, who also stopped by the Dream Fluff, with his dog, Fred, said he was sleeping when his bed suddenly started to shake.

"I was dreaming I was driving," he said. "I thought I was having a trouble with my car," he said with a laugh.

Power was knocked out in the Oakland area minutes after the quake with more than 1,000 customers affected, a Pacific Gas & Electric Co. spokesman said. Crews were investigating what caused the outages.

There were reports of items falling off shelves and broken glass throughout the east San Francisco Bay area.

A spokesman for the area's Bay Area Rapid Transit commuter trains said crews inspected the tracks and found no damage.

A online survey filled out by area residents on the U.S. Geological Survey's web site indicated the quake was felt as far as Napa. This was the most intense earthquake to hit the state since a 4.3 magnitude temblor hit near Aromas, in the Santa Cruz Mountains, on July 2.

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