SIMI VALLEY, Calif. — More than a dozen small earthquakes, all believed to be aftershocks of the deadly 1994 Northridge quake, rattled a wide section of Southern California but caused no injuries, authorities said.

The first of the quakes, with a magnitude of 4.2, struck just before 10 p.m. Monday and was followed minutes later by quakes of magnitude 3.9 and 3.8.

Over the next five hours, there were at least 18 more quakes, measuring 2.9 magnitude or less. Authorities said there were no reports of damage or injuries.

Carlos Pena, a manager of a Denny's restaurant near the center of town, said no pots or pans fell during the shaking, but patrons became uneasy.

"The customers got a little panicky," Pena said. "Most of them stood up and tried to get to the cash register to pay quickly, and one girl couldn't wait and she started to make, kind of like, screaming noises."

All the quakes centered six to seven miles northeast of Simi Valley, which is about 35 miles northwest of downtown Los Angeles.

Seismologist Lucy Jones of the U.S. Geological Survey in Pasadena said all the quakes could be classified as aftershocks to the magnitude-6.7 Northridge quake in 1994, which caused more than $15.3 billion in damage and killed 72 people. About 114,000 homes and buildings were damaged.

There is no reason to believe the latest quakes are a precursor to a bigger quake, Jones said.

"There's nothing about this that tells us, 'Oh, now we need to experience bigger in the next few days.' We had a very similar aftershock back in February," she said.