4.1 Earthquake, 5 Aftershocks Shake Ojai, Ventura

Rattling windows and coffee cups, a magnitude 4.1 earthquake centered northwest of Ojai was felt as far as Ventura on Wednesday.

The 3:09 p.m. quake was followed by five aftershocks, culminating with a 3.6 at 4:18 p.m., Caltech scientists reported.

The epicenter of the quake was 10 miles into the earth close to Wheeler Hot Springs. The earthquake was near, but not on, the important Santa Ynez fault.

It was the most severe recorded in the vicinity of the epicenter in the last century, Caltech seismologist Egill Hauksson said.

No injuries or damage were reported.

For those near the epicenter, “it was a pretty good shake,” said Russell Ahlers Williams, an engineer at Wheeler Gorge fire station six miles north of Ojai. “It shook our barracks pretty good.”

But for those farther away, the quake was so slight that some were not sure what they felt. An employee at Ojai Community Hospital’s emergency room was surprised to hear that the earth had shifted.

“We didn’t have an earthquake. That was a sonic boom,” she said.

Cindy Bassett, an employee at the Ojai police station, said: “The only calls we’re getting are people asking if we had one.”

A Southern California Edison official reported that one customer lost power but was uncertain if the outage was quake-caused.

Hauksson said an unidentified fault line dipping away from the surface at a 45-degree angle caused the quake. It may have been associated with the 20-mile-long San Cayetano fault, but further study will be necessary to confirm that, he said.

Determining the source of quakes can be extremely complicated. Scientists are still not certain which fault caused the devastating 1994 Northridge earthquake.

The Santa Ynez fault, one of California’s major faults, runs 65 miles from near the Los Angeles County line through Ventura and Santa Barbara counties to Gaviota. Scientists say both the magnitude 7.5 Lompoc quake in 1927 and the magnitude 6.3 quake in Santa Barbara in 1925 were associated with the Santa Ynez fault system.

Even though the origin of Wednesday’s quake was close to the Santa Ynez, Hauksson said the quake’s distinctive movement--scientists refer to it as a horizontal strike-slip--tells scientists that the Santa Ynez was not involved.

Will more follow?

Scientists cannot say for sure, but the fact that a 3.6 magnitude aftershock rippled the earth more than an hour later could be a sign of more to come. The most powerful shaker in Ventura County in recent memory was a 5.7 quake in Oxnard in 1973, which caused considerable damage and injuries.

Correspondent Nick Green contributed to this story.