An earthquake jolted San Francisco Bay area residents awake early Friday, breaking glass and rattling nerves, although there were no immediate reports of injuries.

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. It could be felt for up to 10 seconds on both sides of the San Francisco Bay after striking shortly after 4:40 a.m.

More than 1,000 customers in the Oakland area lost power, a Pacific Gas & Electric Co. spokesman said. Crews were investigating the outages.

A dispatcher at the Oakland Police Department said police were getting calls about alarms going off. In Berkeley, an employee at a Safeway grocery store said two large windows broke but there were no injuries.

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