Thursday, March 26, 2009

Bombay Beach earthquake swarm continuing



The Bombay Beach earthquake swarm continues at California's Salton Sea, at the south end of the San Andreas fault. The California Earthquake Prediction Evaluation Council is reported by local papers as saying on Tuesday that there is a 1-5% chance of a large earthquake (up to M7 or so) in the next few days. There was a M4.0 event overnight. So far, 250+ events have been recorded.

The best description and maps I've seen come from the Southern Calif. Seismic Network [right, red dots show the recent activity. The white dots are historical seismicity. Green dots are mud pots and carbon dioxide vents. Credit, SCSN.org]

The earthquake epicenters appear to outline a diffuse zone at the end of the San Andreas fault and a NE-SW trending transform fault across the southern end of the Salton Sea.

California emergency management officials started notifying Arizona counties along the state border today about the potential for a larger event. AZGS staff are advising the Arizona Div. of Emergency Management about the potential geologic impacts on Arizona if there is a big quake in California.