A magnitude-4.3 earthquake was recorded early Monday in Mendocino County, the U.S. Geological Survey said.
The quake struck at 12:16 pm Its epicenter was 8 miles southeast of Willits.
Almost 400 people responded within five hours to the USGS Did You Feel It? site. The 230 of those within 10 miles of the epicenter – in communities including Willits, Potter Valley and Redwood Valley – described the shaking as light. No injuries were reported.
Reports also came from Ukiah, Fort Bragg and Mendocino.
It was the strongest quake in the contiguous United States in the past seven days.
In the Bay Area, a 3.4 quake was recorded early Saturday near Concord.