Swarm of Aftershocks Continues to Jolt Ridgecrest Area

Hundreds of aftershocks continued Thursday in the desert north of Ridgecrest, the site of a magnitude 5.8 earthquake Wednesday, and scientists from Caltech and the U.S. Geological Survey said past patterns in the area indicate that the shaking could go on for months.

“Clusters of earthquakes in Ridgecrest and the nearby Owens Valley are common,” said Lucy Jones of the Geological Survey. “The last time they occurred in Ridgecrest, in 1981-82, they lasted 18 months.”

Jones said aftershocks in the high-4 magnitude range could easily be expected, and added that scientists have not been able to identify signs that the quake cluster is about to come to an end. The strongest aftershocks Thursday--both 4.0--occurred at 12:57 a.m. and 4:48 p.m., according to Caltech.

Caltech seismologist Egill Hauksson said the sequence of quakes, which began Aug. 17 with a magnitude 5.4 on the terrain of the China Lake Naval Air Weapons Station and peaked with Wednesday’s 5.8 in the same area, bears some resemblance to the 1992 Landers-Big Bear sequence in another part of the Mojave Desert, although it has been much smaller.

The Landers quakes began with a magnitude 6.1 on April 22, 1992, peaked with a magnitude 7.5 on June 28, 1992, and continue with more than 50,000 aftershocks.

Meanwhile, geophysicist Frank Monastero, head of a geothermal program at the weapons base, went to the quake epicentral area Thursday, but found no ground cracking or any indication of a surface rupture from Wednesday’s temblor, a base spokeswoman reported.

The quake caused minor damage in several Southland communities and was widely felt.