SAN FRANCISCO (AP) -- A small earthquake hit the San Francisco area on Thursday afternoon, causing a sharp jolt but no immediate signs of damages or injuries.
The quake, with a preliminary 3.9 magnitude, was centered near Berkeley. San Francisco police and officials at University of California, Berkeley, said they had no reports of injuries or damages.
The U.S. Geological Survey said the earthquake hit two miles southeast of Berkeley at 2:31 p.m. According to USGS maps, the quake was actually centered directly beneath UC Berkeley's campus.
Officials at UC Berkeley said they had not received any reports of damage or injuries.
Tami Humphrey, director of a preschool just north of Berkeley, was outside with her students when the quake struck.
"We felt it pretty good. It felt like a drop and then a shake," she said. "The kids didn't even notice."
Officials at Bay Area Rapid Transit said the system's trains were delayed about 15 minutes as workers inspected tracks.
The quake was felt as a sharp jolt in the East Bay area and across the bay in San Francisco.
It came almost 22 years to the day after the Loma Prieta earthquake struck the Bay Area during the 1989 World Series. The magnitude-6.9 quake killed 63 people, injured almost 3,800 and caused up to $10 billion damage.
Thursday's quake came on the same day Californians took part in an annual earthquake preparedness drill at 10:20 a.m. More than 8 1/2 million people signed up to participate in the 2011 Great California ShakeOut.