The quake, which struck at 10:15 a.m. PDT, had a preliminary magnitude of 6.0 and was centered 7 miles southeast of Parkfield, the town known as California's earthquake capital, according to the U.S. Geological Survey. The area is 21 miles northeast of Paso Robles,
"I had stuff everywhere... lamps and pictures and stuff on the floor," said Willa Sell, 77, who lives on a ranch outside Parkfield. "I was happy when it was over. It was a real shaker."
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.
A little more than an hour after the main earthquake, a spokesman for the state Office of Emergency Services said the office hadn't received any reports of injury or damage.
"The aftershocks are tracking toward the northwest, which is good, according to the scientists, because it appears it is not a precursor to something larger," said Eric Lamoureaux, an emergency services spokesman.
The quake was felt along a 350-mile stretch, as far north as San Francisco and as far south as Santa Ana, southeast of Los Angeles, the geological survey said. The Los Angeles County Sheriff's Department reported receiving several calls.
"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 located on the San Andreas fault and it has experienced six similar, magnitude 6.0 earthquakes with apparent regularity — one approximately every 22 years.
The USGS even named its major long-term 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."
The Dec. 22, 2003, earthquake collapsed old downtown buildings in Paso Robles, pitching an 1892 clock tower building onto the street and crushing a row of parked cars. Two people were killed in the state's first fatal quake since the 6.7-magnitude temblor that hit the Northridge area of Los Angeles in 1994.
Since December, many residents of the area have taken precautions to protect their property and valuables from the next inevitable temblor.
"I respect them, let's put it that way," Mary Vanderwert, 57, said by telephone Tuesday from her Paso Robles home. She experienced Tuesday's quake as a series of ripples and vibrations. "It just tickled your feet and then all of a sudden it's jerking and then the whips started."
The USGS estimate of magnitude was strengthened from 5.8, or "moderate," to 6.0, the threshold for a "strong" earthquake. Preliminary magnitudes are determined by seismographs across the planet, and often change as scientists pinpoint where the epicenter is and interpret the data.
A magnitude 5 quake can cause considerable damage and a magnitude 6 quake severe damage, though problems are generally far less severe in remote areas and areas with strong building codes.
"We have good architecture and good building codes in California," Hanna said.
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.