THIS STORY HAS BEEN UPDATED WITH INFORMATION ON ANOTHER QUAKE REPORTED ON FRIDAY.

THE GEYSERS – Residents from Cobb to Kelseyville and as far south as the Bay Area reported feeling one of the county's largest quakes this year which occurred late Thursday.

The US Geological Survey reported a 4.1-magnitude, 0.7-mile-deep earthquake occurred at 9:48 p.m. three miles southeast of The Geysers, four miles west of Anderson Springs and five miles south southwest of Cobb.

The big quake was preceded by approximately 16 seconds by a smaller, 3.-5 magnitude quake centered two miles east southeast of The Geysers. That quake was not added to the US Geological Records until later in the day Friday.

Cobb resident Roger Kinney reported the quake lasted about six to eight seconds. After it began there was a lull and then the motion increased again, he said.

A series of smaller earthquakes followed within an hour, with the largest being a 2.6-magnitude temblor centered two miles east of The Geysers, according to the US Geological Survey.

A total of 105 reports were made to the US Geological Survey by people who felt the large quake, most of whom – approximately 20 – were in Middletown. The area with the second-highest number of reports was Healdsburg, with 18. The San Francisco area also had numerous reports from those who felt the evening temblor.

According to Lake County News records, this is only the second quake of 4.0 magnitude or above to occur in the county this year.

Another quake measuring 4.1 on the Richter scale occurred on Feb. 23, one mile north of The Geysers.

E-mail Elizabeth Larson at This email address is being protected from spambots. You need JavaScript enabled to view it..

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