Moderate California Quake a Drill for ‘Big One’

Despite shaking a large swath of Southern California, a magnitude-5.4 earthquake was not the “Big One” that scientists have long feared. Still, it rattled nerves, causing people to vow to step up their emergency preparations.

The quake, which rocked the region from Los Angeles to San Diego on Tuesday, caused only limited damage and minor injuries, and served as a reminder of the seismic danger below sprawling freeways and subdivisions.

Homes and businesses reported widespread but minor damage, such as fallen ceiling tiles, cracked walls and windows, and warped door frames.

The temblor’s epicenter was located just outside Chino Hills, 29 miles southeast of downtown Los Angeles in San Bernardino County, and it was felt as far east as Las Vegas.

At least 90 aftershocks followed as of Wednesday morning, the largest a magnitude-3.8 that came about 10 minutes after the main quake.

“We were really fortunate this time,” said Capt. Jeremy Ault of the Chino Valley Independent Fire District. “It’s a good opportunity to remember that we live in earthquake country. This is part of living in Southern California, and we need to make sure we’re prepared.”

Chino Hills was incorporated in 1991, so much of the construction is newer and built to modern safety standards, city spokeswoman Denise Cattern said. There were no reports of harm in the city of 80,000, she said.

“We have all the latest building standards and that probably made a difference,” she said.

Cell phone providers, however, were overwhelmed by the event. Cattern said public works employees in the field had to find land lines to call headquarters because their cell phones wouldn’t work.

Sprint Nextel Corp. reported a spike in volume of 800 percent right after the quake, and Verizon Wireless saw the volume jump by 400 percent over that of a typical day. It wasn’t clear how long the systems were overloaded but they were back to normal Wednesday.

“The demand was just incredible,” Verizon spokesman Ken Muche said in Orange County.

Volume was about 40 percent higher than Verizon had projected would occur in a disaster, Muche said Wednesday.

“Whether it’s a freeway or cell network, no network has infinite capacity,” he said. “There were so many calls happening at the same time.”

The magnitude-5.9 Whittier Narrows quake in 1987 was the last big shake centered in the region.

Scientists were trying to determine which fault ruptured Tuesday, but they believe it is part of the same system of faults. The 1987 earthquake heavily damaged older buildings and houses in communities east of Los Angeles.

As strongly as it was felt, Tuesday’s quake was far less powerful than the deadly magnitude-6.7 Northridge earthquake that toppled bridges and buildings in 1994. That was the last damaging temblor in Southern California, though not the biggest. A 7.1 quake struck the desert in 1999.