A magnitude-4.7 temblor struck remote northwest Nevada near the California border early Thursday, marking the largest event in an ongoing “earthquake swarm” that has included hundreds of smaller quakes in recent months.
The swarm could point to the possibility of a larger quake striking the area, scientists at the University of Nevada, Reno said Wednesday.
The series of quakes in the sparsely populated area began July 12 and has increased in intensity in the past week, according to a news release from the university’s Nevada Seismological Laboratory.
The lab had recorded more than 42 quakes greater than magnitude 3, and about 550 over magnitude 2 in recent months.
Alturas, California, where about 2,800 people live, is about 50 miles southwest of the swarm.
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Since Tuesday, four earthquakes over magnitude 4 struck the area, including the 4.7 that hit at 12:34 a.m. Thursday, according to data from the U.S. Geological Survey.
At 7:58 a.m. Thursday, a 4.2-magnitude quake struck in the same area.
The area where the quakes have struck is far from population centers and few have reported feeling seismic activity, according to news reports in Oregon and Nevada. The swarm is centered in Nevada’s far northwestern corner, near far northeastern California and the Oregon border.
The “swarm” is similar to one that occurred in 1968 in Adel, Oregon, lasting several months and producing three earthquakes over magnitude 5, according to the Nevada Seismological Laboratory news release. The Adel swarm caused moderate damage.
A 2008 swarm in west Reno led to a magnitude-5 earthquake as well, causing moderate damage, the lab stated.
Such quake sequences reveal a “small increase in the probability of a larger event,” the lab said.
