A 5.8-magnitude earthquake reported Sunday 53 miles west of Petrolia, California, was one of 10 recorded in the area in 24 hours, according to the U.S. Geological Survey.
The other nine ranged from a 2.5-magnitude quake to a 4.9, and people from hundreds of miles away reported feeling them, the survey said.
Mapping showed the first nine occurred in an elliptical shape that was growing to the west.
Petrolia is a coastal town about 270 miles northwest of Sacramento.
Experts say the epicenter of the 5.8-magnitude quake was 1.3 miles beneath a part of the Pacific where multiple tectonic plates scrape against each other, according to a report by the Berkeley Seismology Lab.
The other nine quakes ranged in depth from a half mile to nearly six miles from the surface, the USGS said.
Petrolia is well known to the state’s geologists. It was 2.5 miles from the epicenter of one of the strongest quakes ever to hit California: a 7.2 on April 25, 1992, that injured 350 people, according to the Berkeley Seismology Lab.
“The region around Petrolia, Cape Mendocino, and Punta Gorda, which are all just 10 miles from each other, is not only the northern terminus of the San Andreas Fault,” the lab reports. “There the interaction between the Pacific and the North American plates fundamentally changes its character.”