A major earthquake jolted the Imperial Valley on Monday evening, setting off power outages in some isolated desert communities, swaying tall buildings in San Diego and rocking large sections of Southern California.
However, damage from the temblor, which was measured at 6.2 on the Richter scale in preliminary estimates, was minor. There were no initial reports of injuries.
Seismologists at the Caltech Laboratory in Pasadena said the quake hit at 5:53 p.m. 10 miles northwest of the tiny desert community of Westmorland. Westmorland, with a population of about 1,500 and located near the southern tip of the Salton Sea, is about 100 miles northeast of San Diego and 195 miles south of Los Angeles.
"It caught us by surprise and, well, scared us," said Imperial County Sheriff's Lt. Michael Hackett in Brawley. "By the unscientific calibrated seat of my pants, I estimated that the ground shook for about a minute and a half."
Based on the early estimates, Lucille Jones, a seismologist with the U.S. Geological Survey in Pasadena, described the quake as "larger, by something on the order of 50%, than the one in Los Angeles" on Oct. 1.
"The little damage we had from this one," she said, "is directly attributable to the fact there's nothing nearby to be damaged."
In Berkeley, University of California seismologists estimated that the earthquake measured 6.4, while the U.S. Geological Survey in Golden, Colo., reported a magnitude of 6.0 for the quake.
The powerful October earthquake centered in the Whittier Narrows area, measured at 5.9 on the Richter scale, caused three deaths and an estimated $213 million in damage.
The Richter scale is a measure of ground motion; every increase by one full number means a tenfold increase in wave amplitude and larger increase in the amount of energy released.
Monday's temblor was preceded by two foreshocks at 5:32 p.m. and 5:52 p.m., both registering more than 4.0 on the Richter scale. Within two hours of the quake, at least 10 aftershocks had been measured, including two in the 5.0 range, Caltech officials said.
Most of the area around the epicenter is lightly populated and damage was reported as minimal. But the earthquake shook area residents, many of whom remember a 6.4 earthquake in 1979--centered near nearby El Centro--which caused an estimated $30 million in damage.
Faults Converge in Area
According to seismologist Jones, the Imperial Valley is an earthquake-prone area in which "the most active faults of Southern California converge."
At the Naval Air Facility in El Centro, about 25 miles southeast of the epicenter, spokesman Bob Haagenson said the quake forced officials to shut down the runway while it was checked for damage.
"It built up for about 45 seconds to a minute, it lost power and then it came back, real strong. . . . But there was no runway damage," Haagenson said.
El Centro Police Sgt. John Jordan said some traffic lights were out as a result of the quake but no damage or injuries were reported.
Robert Taylor, spokesman for the Westmorland Police Department, said the only reported damage resulted from goods falling off the shelves and a cracked window at a local grocery store. Customers dining at the Town Pump restaurant "kind of just waited until it was clear," owner Mary Brown said.
"The juice we use on the prime ribs started splattering all over the grill," she said. "But there's no real damage and nothing has fallen yet. . . . But it was still real bad. One of our girls took off for home."
Telephone service to the Imperial Valley was temporarily affected by damaged lines, authorities said. In Niland, population 1,000, electricity was knocked out in part of the town, said Fire Department spokesman Len Mara, but no damages or injuries were reported.
The earthquake triggered an "unusual event" declaration at the San Onofre nuclear power plant near San Clemente, but there was no damage or any interruption in service, officials said.
"We have instrumentation there that registered it, and some people felt it," said David Barron, a spokesman for Southern California Edison Co. "But there wasn't any problem at all associated with the plant." The unusual event procedure, which includes notification to the U.S. Nuclear Regulatory Commission, is the NRC's lowest-level emergency declaration.
In San Diego, the quake struck while City Council members were meeting on the 12th floor of City Hall. Walls, wires and a drop ceiling creaked and quivered for about 30 seconds, causing council member Abbe Wolfsheimer and some council aides to scramble toward a wall while keeping a wary eye on the ceiling.
In Los Angeles, county fire dispatcher John Tabak reported calls "from a few people asking if we did have an earthquake. . . . They were just saying chandeliers were shaking and that they thought they had an earthquake but they weren't sure."
Palm Springs fire officials said they received about 20 calls concerning the shaker, but no damage reports.
In the town of Calexico, just north of the Mexican border, fire officials said they were besieged by calls but there were no reports of damage or injuries.
The 1979 earthquake was along the major Imperial fault line. But while officials Monday said they had not yet pinpointed the fault on which the new earthquake occurred, they added that it was a different one than in the 1979 quake, which caused 100 injuries.
Times staff writer Marita Hernandez assisted on this story.