Earthquake In Northern Sonoma County Felt Across Bay Area: USGS

SONOMA COUNTY, CA — A 4.1-magnitude earthquake hit an area of unincorporated Sonoma County near Cobb Mountain and The Geysers early Wednesday morning, according to the United States Geological Survey.

The temblor was recorded at 4:57 a.m. in northeast Sonoma County, around 2 miles from the prominent Lake County mountain and near the Sonoma-Lake county line.

There were no immediate reports of injuries or damage from the quake that according to the USGS, struck about 1 mile from The Geysers, 3 miles from Cobb and 24 miles from Santa Rosa.

Response submitted to the USGS indicated the earthquake was felt in the North Bay cities of Healdsburg, Cloverdale, Geyserville, Calistoga, Windsor, Clearlake, Hidden Valley Lake, Middletown, Kelseyville, St. Helena, Santa Rosa, Napa, Sonoma, Petaluma and Belvedere-Tiburon, and as far away as San Francisco, Albany, Mountain View, Capitola and Chico.

Two earthquakes — a 3.7-magnitude and a 2.8-magnitude —struck just minutes apart Feb. 26 in the same general area, near The Geysers and Cobb.

According to the USGS:

"The Geysers Geothermal Field is located in a tectonically active region of Northern California. The major seismic hazards in the region are from large earthquakes occurring along regional faults that are located miles away from the geothermal field, such as the San Andreas and Healdsburg-Rodgers Creek faults. However, activities associated with the withdrawal of steam for producing electric power cause or induce small quakes to occur in the field. These smaller quakes are frequently felt by those who work at the field and by nearby residents."

Bay City News Service contributed to this report.