A magnitude-6.5 earthquake was reported early Thursday off the coast of Northern California.
The quake, downgraded from its initial magnitude of 6.8, was about 100 miles off the coast of Eureka, California, a city of about 27,000 people 100 miles south of the Oregon border. Shaking was reported along the Northern California coast, including Ferndale, Eureka and nearby seaside communities.
A tsunami warning was not expected, according to the Tsunami Warning Center. There were no reports of injuries or damage.
A magnitude-4.7 earthquake was reported about one hour later in the same area.
The region nearly 300 miles north of San Francisco has a history of strong and damaging quakes.
In January 1922, a magnitude-7.3 earthquake off the coast of Humboldt County damaged houses and water lines. The shaking, which also triggered landslides, was felt from the northernmost part of the state south to San Francisco.
A small tsunami was reported, according to the USGS.
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In April 1992, the Cape Mendocino Earthquakes, with magnitudes 7.2, 6.5 and 6.7, rattled the region. The first quake occurred April 25 about 30 miles southwest of Eureka. Nearly 100 people were injured and a tsunami generated waves in Northern California and Hawaii.
The next day, a magnitude-6.5 quake shook the same area, causing more damage in Ferndale, Petrolia and Fortuna. About four hours later, a magnitude-6.7 earthquake was reported.
More recently, a magnitude-6.8 earthquake shook the area in March 2014. The area had a magnitude-5.6 earthquake in February 2012.