A series of small earthquakes jolted an area of central California, but there were no reports of damage.

The largest in the sequence—a magnitude-4.1 temblor—hit at 6:30 a.m. Friday and was centered 6 miles north of Coalinga at a depth of 7 miles, the U.S. Geological Survey said.

The quake wasn't too strong and lasted four or five seconds, said Christine Mercer, a dispatcher with the Coalinga Police Department.

"You could kind of hear the rumble and then there was a jerk and that was it," she said.

Mercer said police received numerous calls, but none reported any damage or injuries.

Scientists said the quakes occurred in a fault zone that experiences magnitude-3 or magnitude-4 events every year or so.

"There is nothing unusual about the recent activity," Jennifer Andrews, seismologist at the California Institute of Technology, said in a statement.