A swarm of earthquakes, including one measuring 5.1 magnitude and another 4.9, continued Wednesday and early Thursday in the same remote area of Nevada, according to the USGS.
More than 50 earthquakes ranging in magnitude from 2.5 to 5.1 shook in the same remote area of Nevada over a 37-hour span Tuesday, Wednesday and early Thursday, according to the U.S. Geological Survey. They are technically aftershocks to a 6.5 magnitude quake that shook the same area in May.
The strongest of at least 55 temblors that were centered near Mina, Nevada, about 116 miles southeast of Lake Tahoe, struck at 3:33 p.m. Pacific time Tuesday, the USGS said.
The string of quakes continued into Tuesday evening and early morning hours Wednesday, then with less frequency into early Thursday morning, the USGS said.
A USGS spokesperson said the swarm is a series of aftershocks related to the 6.5 magnitude Monte Cristo earthquake on May 15.
"The recent seismic activity in the area is a part of a typical aftershock sequence following that magnitude 6.5 mainshock earlier this year," spokeswoman Elizabeth Goldbaum said in an email Thursday. "Since all the events ... in this area have been less than the magnitude of the mainshock (including the events over the past few days), these are all considered aftershocks, according to our USGS research geologists."
Nevada State Geologist Dr. James Faulds told NBC Bay Area there have been more than 6,500 aftershocks since the May 15 quake, which occurred along the Walker Lane Fault, the same fault line where the 7.1 magnitude Ridgecrest earthquake rattled Southern California in June 2019.
The Monte Cristo quake struck in the same area at 4:03 a.m. local time May 15 at a depth of just 1.8 miles, the USGS said. The agency said at the time aftershocks were typical and expected to decease in frequency over time. But the latest cluster seemingly is an increase in the strength of that aftershock activity.
Mina, Nevada, is about 350 miles due east of San Francisco.