UNR seismologists: Earthquake swarm to keep shaking Nevada
(Photo: Courtesy of University of Nevada, Reno)
A recent swarm of earthquakes continues to shake Northern Nevada as local seismologists monitor the on-going activity that includes three quakes larger than magnitude 4 since mid-July – with the strongest quake reaching 4.6.
The swarm includes 209 earthquakes reaching a magnitude of 3, 20 earthquakes of magnitude 4 and five earthquakes of magnitude 4.5 or greater. The recent largest earthquake was a magnitude of 4.7 recorded in early November last year, seismologists said in a news release Monday.
"Although the activity is pretty far from population centers, that doesn't help the ranchers and residents near Vya, Nev. east of Cedarville, Calif., who feel the shaking from nearly every earthquake larger than about magnitude 3," Ken Smith, a seismologist at the University of Nevada, Reno's Nevada Seismological Laboratory, said in a statement Monday.
"Since last July, we've been able (to) locate 5,610 earthquakes in the swarm."
The swarm has included three periods of magnitude 4 earthquakes, Smith said. The first period was in November and early December of last year. The second was recorded in January and the most recent wave began in mid-July, he said.
Seismologists said they believe the activity stems from a fault or faults that dip steeply to the southeast and strike north-northeast.
"A temporary station installed in late November 2014 in the Coleman Canyon area has really helped improve locating events," Smith said in the statement. "We estimate that we can only pinpoint about 5 to 10 percent of everything we can see on this closest station since the seismic network station coverage is very sparse in northwest Nevada. Sharing several stations with our partner network at the University of Washington has also helped in monitoring the activity."
"Sharing several stations with our partner network at the University of Washington has also helped in monitoring the activity," he said.
The swarm could also be related to volcanic activity. Still, scientists haven't found direct evidence to indicate if the swarm is driven by volcanic processes, seismologists said.
The quakes are believed to be long-lasting, but typical tectonic sequence stemming from extensional deformation. It's something characteristic of earthquakes in the western Great Basin, Graham Kent, director of the Nevada Seismological Lab, said in a statement Monday.
"This is somewhat in character with Nevada earthquake activity, with swarms of thousands of small earthquakes, sometimes followed by a larger one," Kent said in a statement.
"It's a good reminder that Nevada is the third most seismically active state in the nation and that we should all be prepared," he said in the statement.
In every swarm, there's a small chance for a larger earthquake, seismologists said. Even after a year of activity, scientists can't predict when that big quake will strike.
Still, Nevada has not felt a magnitude 7 earthquake in 60 years.
"(In) the first 54 years of the 20th century, we had seven earthquakes of magnitude 6.5 or larger and haven't had one since," Kent said in the statement. "We haven't had the big one since the Dixie Valley/Fairview Peak sequence in 1954 east of Fallon, which was two magnitude 7s four minutes apart.
"Since then, Nevada's population has grown 13-fold," he said.
In 2008, an earthquake with a magnitude of 6 shook Wells – the largest event to hit Nevada in 42 years. The state can usually expect three magnitude 7 earthquakes per century and one magnitude 6 or larger every decade, Kent said in the news release.
Officials said they encourage citizens to prepare for the potential for a stronger ground shaking.
7 tips to prepare for an earthquake
Identify hazards and secure moveable items around you.
Plan for the worst. Create a disaster plan and figure out how to communicate in any emergency.
Keep supplies in a convenient location in case of a disaster.
Minimize financial hardships. Organize important documents, strengthen your property and consider insurance.
Drop cover and hold on when the earth shakes.
Evacuate if necessary and help the injured.
Reconnect with others, repair the damage and rebuild the community.
For more information visit www.earthquakecountry.org or www.seismo.unr.edu
Source: Earthquake Country Alliance.
At a glance:
Nevadans can register for the 2015 Great Nevada ShakeOut as part of a worldwide event to practice how to drop, cover and hold on during an earthquake. The ShakeOut is set for 10:15 a.m. on Oct. 15, according to the event website.
To register, visit www.shakeout.org/nevada/
Source: Great Nevada ShakeOut
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