COBB, Calif. – A 3.1-magnitude earthquake was reported near The Geysers geothermal steamfield early Saturday morning.

The US Geological Survey said the quake occurred at 12:10 a.m. one mile northeast of The Geysers, four miles west southwest of Cobb and six miles west northwest of Anderson Springs at a depth of 2.2 miles.

The USGS report is preliminary, and the size of the quake may later be updated.

As of 12:30 a.m., only one shake report had been submitted to the survey from Calistoga.

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