3,000 earthquakes since July 4, and more big ones likely coming

Southern California could experience another sizable earthquake over the next week, seismologists said Saturday.

The U.S. Geological Survey has calculated a 27% probability the region will be hit by a magnitude 6 or greater quake in the coming days, according to Caltech seismologist Egill Hauksson.

“We’re likely to see maybe one or two of those in the next week,� he said at a weekend news conference.

The USGS estimates that the probability of a magnitude 7 or greater earthquake hitting within the next week has fallen to 3%, down from 6% on Friday.

“That probability is over the next week, but it is mostly packed into the hours and days after the main shock,� Caltech seismologist Doug Given said.

In other words, the probability that we will experience another earthquake of magnitude 6 or higher is dropping by the minute, he said.

“Every minute that ticks by, it becomes less likely,� he said.

The heightened seismic activity comes in the aftermath of a magnitude 7.1 earthquake that hit near the town of Ridgecrest, about 125 miles northeast of Los Angeles, on Friday night. That was preceded by a 6.4 earthquake in the same area the morning of the Fourth of July. Scientists are now calling that a foreshock.

Since the Fourth, Caltech seismologists have detected at least 3,000 smaller earthquakes.

(Chris Keller / Los Angeles Times)

Those include 340 earthquakes with a magnitude greater than 3; 52 that registered above 4; and six with a magnitude greater than 5, Hauksson said Saturday.

In total, this earthquake sequence is expected to generate about 34,000 aftershocks with a magnitude 1 or greater over the next six months, he said.

This week’s earthquakes were the strongest to hit the area in 20 years. No deaths or major injuries have been reported, but homes and roadways were damaged, particularly in the Ridgecrest area.

Gov. Gavin Newsom has requested a presidential emergency declaration for the affected regions.

With the fear of more aftershocks, Jimmy and Jackie Roberts are taking no chances of staying in their home.

The couple was assembling a 20-foot-by-10-foot canopy at their Ridgecrest home on Desert Candles Street. They last used the blue canopy at their wedding 10 years ago and planned to put a tent and air conditioner under it.

“We’re staying in it for the next three days,� she said. “We have to keep our three dogs and four birds safe.�

She said that they and many neighbors had slept in their cars last night on the street. “We were all out there,� she said. “We were afraid.� Her biggest fear, she said, is another quake will hit and people will run out of water in the 90-degree temperatures. She also expects more neighbors to sleep in tents or cars until dangers clear. “My other neighbor is buying a camper today,� she added.

Ridgecrest Mayor Peggy Breeden encouraged residents to take safety precautions over the next few days until the seismic activity subsided. She said the town shouldn’t suffer long-term consequences from the last several days. She doesn’t believe residents will flee to other cities.

“We’re used to this,� she said after a news conference. “We live in the earthquake capital of the world, so I’m told. Our people are strong.�

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Times staff writers Deborah Netburn and Mark Puente contributed to this report