Aqueduct Is Closed in Southland Quake

A 5.2 magnitude earthquake centered near the Grapevine on Interstate 5 was felt widely throughout Southern California Friday afternoon. There were no reports of injuries, but there was damage to several power-switching stations and the California Aqueduct was shut down at least until today

The temblor occurred near the site of the great 1857 earthquake on the San Andreas Fault which, at about 8 magnitude, was the most powerful recorded in Southern California’s modern history.

But Friday’s quake was on the Garlock Fault and not on the San Andreas, according to scientists at the Caltech seismological laboratory and the Pasadena field office of the U.S. Geological Survey.

The Garlock Fault runs from the south end of Death Valley to an intersection with the San Andreas in the general vicinity of Lebec, 70 miles northwest of Los Angeles. It has been associated with few sizable earthquakes in this century, but has produced magnitude 7 quakes in prehistoric times, according to the Geological Survey’s Lucille Jones.

Residents in Gorman and Lebec described the 4:06 p.m. quake as a strong jolt which shook a few things off shelves and sent some boulders cascading down on northbound lanes of Interstate 5. Traffic on the highway was not halted, however.

Felt in Downtown L.A.

The quake was felt mildly in downtown Los Angeles and the San Gabriel Valley and a little more strongly, as a rolling motion, in the San Fernando Valley. It was felt as far north as Porterville in the San Joaquin Valley, as far east as Barstow and on the coast in the vicinity of Santa Barbara.

It was followed by several aftershocks, including a 4.0 jolt at 4:22 p.m. and a 3.4 shock at 6:56 p.m.

“The first thing that scared us was the rumbling noise,” said Dawn Yates, who lives near Gorman. “It was really loud. Then you could hear the sound of things on the shelves shaking. And the chandelier was rolling back and forth. Even our 17-month-old (child) felt it. When it hit, he stopped walking and put his hands against the wall.”

‘Felt Like a 6’

“It felt like about a 6 to me,” said Doug Jacobs of Lebec, a tow truck operator. “There was no damage around my place, but it shook us pretty good.”

A cashier at the Caravan coffee shop in Gorman said the earthquake set a heart-rate machine in the shop to ringing.

The California Aqueduct was shut down over its entire 440 miles from Tracy in Central California to Perris in Southern California as a result of a power failure at two pumping stations, according to a Metropolitan Water District spokesman.

The aqueduct supplies more than half the water in Southern California, but there were no reports of damage beyond the power failures and service is expected to resume long before any shortages develop.

A spokeswoman for Southern California Edison, meanwhile, said power supply lines were broken at the company’s Magumden switching substation near Bakersfield, and crews were sent to the unmanned Pastoria substation near Gorman to inspect for damage. She said other utilities also were telling Edison of substation disruptions.

The spokeswoman, Debbie Van Ness, said the utilities were able to compensate for the loss from other supplies and there were no disruptions of service in populated areas.

An earthquake measuring more than 5 can do moderate damage and cause injuries if it is centered in a populated area. But the area of the epicenter Friday is only sparsely populated.

By comparison, last October’s Whittier Narrows earthquake was about four times stronger than Friday’s. Earthquake magnitudes have long been assessed in terms of the Richter scale, but recently scientists have begun using a variety of scales to produce a composite measurement.

No Accidents Reported

There is considerable traffic passing at any given moment up and down the Grapevine, where the twisting highway rises from the San Joaquin Valley into the Tehachapi Mountains, but the California Highway Patrol said there were no accidents along the highway as a result of the earthquake.

The 1857 earthquake on the nearby San Andreas ruptured the surface of the Earth from the San Bernardino Valley to the Cholame Valley, a distance of more than 225 miles. The shaking, however, was most intense at Ft. Tejon, just above the present Grapevine.

The 600-mile-long San Andreas is the predicted fault for the “Big One” expected to strike Southern California sometime in the future. But just where along its length that quake will be centered is unknown.

Caltech seismologist Kate Hutton said it is possible Friday’s quake could put stress on the San Andreas, which she said is about 10 miles from the epicenter. She also noted that there is about one chance in 20 that a shock such as Friday’s could be a foreshock of a much larger temblor.

Times staff writer Steve Harvey contributed to this story.