SAN FRANCISCO – A light earthquake rattled the San Francisco Bay area Friday night.

The U.S. Geological Survey's preliminary report put the quake at a 4.0-magnitude.

The temblor's epicenter was near Alamo, Calif., about 28 miles east of San Francisco.

There were no reports of damage or injuries in Alamo or surrounding communities, said Jimmy Lee, a spokesman for the Contra Costa County Sheriff's department.

The quake hit just after 9 p.m. and could be felt throughout the region. Residents throughout the region reported that they felt a fast, strong shake that quickly dissipated.

There has been at least one minor aftershock with a preliminary magnitude of 1.9, said Leslie Gordon, a USGS spokeswoman.

Fans at the San Francisco Giants' waterfront ballpark felt a jolt during the game with the Pittsburgh Pirates, but there was no interruption.