4.2-magnitude California quake rattles world’s largest geothermal field, USGS reports

A 4.2-magnitude earthquake struck the California coast north of San Francisco on Sunday afternoon, the U.S. Geological Survey reports.

The 1.3-mile deep quake hit near The Geysers at 12:34 p.m. Pacific time, according to the USGS. Dozens of people from as far away as Santa Rosa reported feeling the tremor to the agency.

The earthquake follows dozens of smaller tremors, most falling below 2.0 magnitude, in the area in the past seven days, including a 3.7-magnitude quake Saturday, the USGS reports.

The Sunday afternoon quake was followed by at least three more small quakes ranging from 1.8 to 2.3 magnitude.

The Geysers, the world’s largest geothermal field, lies in the Mayacamas Mountains in Sonoma County approximately 72 miles north of San Francisco, and contains several geothermal plants. It’s the site of frequent earthquakes, the USGS reports.

The Kincade Fire began near The Geysers on Oct. 23. The fire has consumed nearly 78,000 acres and is 76 percent contained, the California Department of Forestry and Fire Protection reports.

Magnitude measures the energy released at the source of the earthquake, the U.S. Geological Survey says. It replaces the old Richter scale.

Quakes between 4.0 and 5.0 magnitude are frequently felt but rarely cause much damage, according to the USGS.

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Don Sweeney has been a newspaper reporter and editor in California for more than 25 years. He has been a real-time reporter based at The Sacramento Bee since 2016.