The earthquake, which struck at 10:15 a.m. PDT, was centered 9 miles south of Parkfield and 17 miles north east of Paso Robles, scene of an earthquake that killed two people in December 2003, according to the U.S. Geological Survey.
A series of aftershocks quickly rattled the area, one with a preliminary 5.0 magnitude four minutes after the main earthquake and three others 4.1 or above.
"Typically, when you get an earthquake of this size, you will get damage to weak structures, masonry-type structures. You get broken glass, a lot of things thrown off of shelves," Robert Uhrhammer of the University of California-Berkeley Seismology lab told KCBS-AM.
Paso Robles police said there were no immediate reports of damage or injuries. Thousands of people from Santa Ana to Sacramento reported feeling the quake.
"It rattled everything hanging on the walls and the chandelier was swinging. It didn't do any damage to our house. There were two shakers, one right after the other," said Ben Brown, who lives in Paso Robles.
jolted the central California coast, killing two people, injuring dozens and wrecking a landmark clock tower in Paso Robles.
"It was a pretty good jolt here, real reminiscent of the one prior," said mayor Frank Mecham on KCBS-AM. "Wasn't as long and wasn't as violent, but it was substantial."
Parkfield, population 37, is known as the earthquake capital of California. Located on the San Andreas fault, six similar, magnitude 6.0 earthquakes have occurred on the San Andreas fault near the town with apparent regularity — one approximately every 22 years.
The USGS even named its major longterm earthquake research project the Parkfield Experiment.
"This is earthquake country. It's a larger earthquake than what usually occurs, but it's not unprecedented," said USGS spokeswoman Stephanie Hanna. "We expect big earthquakes in this area, but don't know when they'll occur."
KCBS-AM's George Harris reports the Scott Peterson murder trial in Redwood, Calif., went into recess because of the tremor.
"Several of the jurors were visibly shaken after this side-to-side motion was felt throughout this area," he said.