Tuesday, March 10, 2020

Ten Quakes In 24 Hours Off Northern California Coast


Ten quakes reported in 24 hours off Petrolia, California




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.
USGS data shows the most recent was a 3.3 magnitude that occurred around 7 a.m. Monday off Ferndale, about 46 miles west of Petrolia.

The 5.8 quake happened around 8 p.m. Sunday and more than 2,600 people reported feeling light to strong shaking, according to a survey page set up to take reports.
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 Pacificwhere 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.”


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