West Coast Quake

It still isn’t the one I predicted, but there was at least one earthquake in California today.

4.0 quake near El Cerrito preceded by smaller 2.9 shaker, officials say

By Robert Salonga,

Contra Costa Times

USGS Map

EL CERRITO -- A magnitude 4.0 earthquake centered in West Contra Costa County rattled homes throughout the Bay Area early this morning, and officials are exploring reports of a 2.9 temblor that preceded it.

"It looks like there might have been two earthquakes," said David Schwartz of the U.S. Geological Survey.

The discovery of the precursor quake would be in line with residents' reports of feeling a jolt and then a rolling sensation. The earthquake that grabbed the region's attention was a 4.0 reported at 5:33 a.m. originating one mile north of El Cerrito in the middle of the Mira Vista Country Club.

According to USGS readings, it was located 5 miles deep along the Hayward fault. It was followed by a

2.0 aftershock at 6:03 a.m. and a 1.2 shaker at 6:29 a.m.

But since those registered, it appears that a 2.9 earthquake occurred 8 seconds before the 4.0 quake, according to the USGS. Schwartz said seismologists are looking to clarify the new reading and rule out computer issues, such as the one that reported a parallel quake in Tiburon that was quickly determined to have been an errant report.

But Schwartz said the retroactive 2.9 reading will likely stay.

There were no immediate reports of serious injury or damage. BART stopped its trains for five minutes after the earthquake to perform routine track inspections. Riders should expect up to 10-minute delays until the system gets back up to speed.