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MILFORD, Beaver County — Scientists say dozens of minor earthquakes recorded in Beaver County over the past week, including a pair of magnitude 3 earthquakes in recent days, are likely a result of underground liquids bubbling but there's no reason to be alarmed.
The U.S. Geological Survey has recorded at least 60 mostly minor earthquakes in the past week, as of Tuesday afternoon. The largest of those were 3.2 and 3.0 magnitude earthquakes that were centered about 5 miles southwest of Milford on Sunday and Monday, respectively.
So far all but six were below 2.5 magnitude over the past week, according to the agency's data. The weakest was an 0.8 magnitude earthquake recorded early Tuesday morning.
The recent patterns caught the eye of University of Utah Seismograph Stations scientists because they are much different than last year's much larger 5.7 magnitude earthquake in Magna, or most earthquakes in general. Experts said they couldn't find a clear mainshock that set off the chain of earthquakes.
Katherine Whidden, a research scientist at the University of Utah Seismograph Stations. said that it appears to be an example of an "earthquake swarm" instead, or earthquakes caused by other underground movements.
"These swarms tend to be associated with hydrothermal fluids — hot water," she explained, in an interview with KSL.com on Tuesday. "We don't always know what causes a swarm but they tend to be associated with hydrothermal activity."
She pointed out that many earthquakes near Yellowstone National Park are caused by the same reason.
There is currently an energetic eq swarm occuring south of Milford, UT. An earthquake swarm is an earthquake sequence with no clear mainshock. Eq swarms are often associated with fluids or in areas of weak crust.
— UUSS (@UUSSquake) March 30, 2021
The eq swarm south of Milford is unlike the Magna eq where
(1/2) pic.twitter.com/Bl6bLKH6h0
The location of the earthquakes isn't exactly a surprise for scientists. Whidden said they are happening away from the Wasatch Fault, but it's an area that's experienced seismologic activity since at least as far back as 1908, which is when there was a magnitude 5 earthquake that rattled the region. There have been a few magnitude 4s and 3s between then and the series of earthquakes that began over the past week.
It's unclear when the swarm might subside. The good news is that scientists said that the swarm doesn't mean a larger earthquake is on the horizon.
"We could have bigger earthquakes as a part of the swarm, but I would be surprised if we had a really big earthquake as a result of this. They tend to be smaller and a lot of little earthquakes," she said.
If anything, the earthquakes are just a reminder that Utah is an area prone to seismic activity.
"We can have a large, damaging earthquake at any time," she added. "The best thing that we can do is be prepared."
