2 Earthquakes Strike Lake County Minutes Apart: USGS

LAKE COUNTY, CA — Two earthquakes struck three minutes apart Wednesday morning near the community of Cobb in Lake County, the U.S. Geological Survey reported. The first quake was centered 3.7 miles west of Cobb and was recorded at 10:31 a.m. at a magnitude of 2.8; the second, stronger quake was recorded at 10:34 a.m., according to the USGS.

It was a 3.7-magnitude temblor and struck 3.5 miles west of Cobb at a depth of a half-mile, according to preliminary information from the USGS.

The 2.8-magnitude first quake struck a mile below the Earth's surface. It was centered 4.2 miles from The Geysers, 6.6 miles from Anderson Springs, 10.4 miles from Kelseyville and 42.3 miles from Santa Rosa.

The stronger 3.7-magnitude second quake was centered 4.4 miles from The Geysers, 6.6 miles from Anderson Springs, 43.7 miles from Santa Rosa and 31.4 miles from Ukiah.

Folks across Lake, Sonoma and Napa counties — including in Calistoga, Santa Rosa, Clearlake, Windsor, Kelseyville, Geyserville, Lower Lake and Hopland — experienced some shaking from one or both of the quakes, according to responses posted at Earthquake.usgs.gov

Did YOU feel any shaking? [Tell us in the comments section below.]

A Patch reader who lives in Cobb — not far from the seismically-active Geysers in northern Sonoma County — told Patch that on average, she experiences at least one 4.0-magnitude earthquake per year.

According to the USGS, here's why:

"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."