The United States Geological Survey announced on its website that the quake occurred just after 9 p.m. about 5 miles east of Yountville.
The earthquake was recorded at a depth of about four-and-a-half miles, according to the USGS. Yountville is a town of about 3,000 people in California's wine-growing Napa Valley region.
It was not immediately clear if the quake had caused any damage.
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