A magnitude 3.7 earthquake struck onshore near Rio Dell in Humboldt County on Friday morning, the U.S. Geological Survey said.
The 7:42 a.m. quake was centered about 4 miles south-southwest of Rio Dell, or 24 miles south of Eureka, the USGS said.
A Humboldt County sheriff's dispatcher said there were no initial reports of damage or problems from the shaker.
Minor earthquakes in the magnitude 3 range are common in the region, though many of them strike off-shore.
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