Another Quake Shakes California

A moderate earthquake (search) jolted an isolated area of central California on Wednesday, triggering a rock slide that closed part of a highway. The quake was unrelated to a larger temblor that rattled a nearby area a day earlier.

The magnitude 5.0 quake could be felt as far south as Los Angeles — 80 miles away — but it apparently caused little damage outside of the rock slide.

It struck at 3:54 p.m. and was centered 17 miles northeast of Arvin. The epicenter was about 140 miles southeast of Tuesday's magnitude 6.0 temblor, which was centered near Parkfield, a town of 37 people known as California's earthquake capital.

"This is actually a new earthquake, this is not an aftershock," said Anthony Guarino, a seismic analyst for the California Institute of Technology (search) in Pasadena.

There have been more than 500 aftershocks from the earlier quake. Two of the biggest, 5.0 and 4.5, shook the region Wednesday morning.

The rock slide closed at least one lane of state Highway 178 in a canyon 20 miles west of Lake Isabella (search), California Highway Patrol Officer Nathan Hunt said. A couple of vehicles were involved, but Hunt could not provide further details.

"There was a roll for a couple of seconds, but it wasn't a strong jerk," said Lupe Vasquez, a dispatcher for the police department in Arvin.

Bakersfield police spokeswoman Mary DeGeare said dispatchers received about a dozen calls from people reporting the earthquake.

"It was obvious it was an earthquake. It was more of a jolt than the rolling sensation they felt yesterday," she said.

Both earthquakes will be examined by scientists who have been looking at links between separate quakes in California that occur far apart, Guarino said.

"The likelihood is that both this earthquake and yesterday's earthquake will have their own aftershocks," said Susan Hough, a U.S. Geological Survey seismologist. "Those sequences will continue to die down, and there's maybe a one in 20 chance that one of these earthquakes will be a foreshock to something bigger."

For example, the deadly 6.7-magnitude temblor that hit the Northridge area of Los Angeles in 1994 was preceded by an earthquake sequence in the Salton Sea area.

Scientists said that Tuesday's quake could end up being a boon in their earthquake research. The area of the San Andreas fault where that quake struck is a seismic hot spot that has produced similar temblors every two or three decades and is among the most-monitored quake sites in the world.

"It's going to be a lot of data that we can look at," said Andy Snyder of the U.S. Geological Survey. "It ensures a good payoff."