No Damage From 4 Mild Southland Temblors

Four “very typical Southern California earthquakes” rumbled through the Southland Monday night and Tuesday, rattling a few residents but causing no reports of injury or major damage.

An earthquake measuring 3.5 on the Richter scale struck southern Orange County at 11:03 p.m. Monday, the Seismology Laboratory at Caltech reported.

The temblor, centered in Newport Beach near Corona del Mar High School, was felt by hundreds of Orange County residents, some of whom heard it as a loud “thump.” Local officials, however, said they had no reports of injury or damage.

“What earthquake?” said a dispatcher at the Orange County Fire Department.

But officials at Big Bear Lake noticed their quake.

“This was kind of like a sonic boom,” said dispatcher Dorie McDonough of the San Bernardino County Sheriff’s Department in Big Bear, 90 miles northeast of Los Angeles.

The 3:13 a.m. quake measured 3.7 on the Richter scale and was centered three miles north of Big Bear Lake, Caltech seismologist Kate Hutton said.

San Bernardino County fire and sheriff’s officials said no injuries or damage were reported.

Two more earthquakes shook the Southland Tuesday night. The temblors occurred less than three minutes apart about 8 p.m.

The first was centered about 45 miles east of Ensenada in Baja California and registered 4.5, Finn said.

Three minutes later, an aftershock to last week’s 6.3 and 6.1 temblors in the Superstition Hills of Imperial Valley hit 11 miles west of Westmorland. The quake registered 4.6, Finn said.

No damage or injuries were reported in any of the temblors, officials said.

Hutton noted that Newport Beach and Big Bear quakes are a common phenomenon for the Southland.

“We get a three-plus at least once a week somewhere in Southern California, maybe twice a week,” she said. “They were really very typical Southern California earthquakes.”

While each temblor releases some of the pressure that could lead to a major earthquake, Hutton said, these two will do little to forestall the major earthquake expected to strike California eventually.

“Every earthquake releases some pressure, but it’s really not enough,” she said.

Hutton said that Caltech scientists had not determined which fault lines were responsible for the temblors.

The Pacific Coast has been shaken by several earthquakes in recent weeks.

On Monday morning, a powerful undersea earthquake registering 7.4 to 7.7 on the Richter scale struck Alaska and Western Canada. Many coastal residents fled for safety from a possible tsunami, or huge wave resulting from underwater disturbance. No giant wave materialized.

No injuries were reported in Monday’s Alaska quake, which followed a 6.9 temblor in the same area on Nov. 16.

On Nov. 24, a temblor measuring 6.3 on the Richter scale struck along the Mexican border and was felt through much of Southern California.

The Richter scale measures the strength of an earthquake at the temblor’s center, with each full step representing a strength about 10 times as great as the preceding step. Thus, a quake measuring 3.7 is 10 times stronger than one measuring 2.7.