SALT LAKE CITY – Researchers at the University of Utah say an unusual series of earthquakes that occurred in central Utah in 2018 and 2019 are reminiscent of old volcanoes in the region. Fortunately, they say there are no indications of an imminent eruption.
The study, first published in Geophysical Research Letters last month, focused on a pair of special earthquakes in the Black Rock Desert near Fillmore. One of the central earthquakes in Utah occurred on September 12, 2018, and the other – on April 14, 2019. The earthquakes registered 4.0 and 4.1 in magnitude, respectively, and caused several aftershocks.
The location of the two earthquakes is the volcanic field in the Black Rock Desert, which is located in central Utah between I-1
In addition to the earthquakes discovered by the Utah Regional Seismic Network, they were captured by temporary seismic equipment used less than 20 miles from the desert to monitor a geothermal well for a different project.
A team of researchers from the University of Utah, USGS and the University of Iowa set out to analyze the data. The temporary equipment helped detect 35 aftershocks after the 2019 earthquake, which was almost double the normal system.
They found that the quake was 1.5 miles below the surface, which is quite shallow for earthquakes. For example, a magnitude 5.7 earthquake that shook the Wasach front last year occurred about 6 miles below the earth’s surface; the central earthquakes in Utah in 2018 and 2019 are not related to the earthquake in Magna, the largest since 1992 in Utah.
In addition, earthquakes do not produce the “shear waves” that are characteristic of Utah earthquakes. The frequency of seismic energy was also much lower than typical earthquakes in Utah, said Maria Messimeri, a doctoral researcher at seismographic stations at the University of Utah and lead author of the study, in a news release Tuesday.
“Because these earthquakes were so shallow, we could measure surface deformation (due to earthquakes) using satellites, which is very unusual for such small earthquakes,” she said.
The data led researchers to believe that earthquakes were not caused by colliding faults like most earthquakes in Utah; rather, they said their research showed that these quakes were the result of continued activity in the volcanic field below the desert.
Messimeri said both earthquakes were likely to have been caused by either magma or heated water that approached the surface and caused the earthquakes.
“Our findings show that the system is still active and that the earthquakes are likely the result of fluid-related movement in the common area,” she said. “Earthquakes can be the result of squeezing liquid through a rock or the result of deformation by the movement of a liquid that has highlighted surface faults.”
The good news, she added, is that there is no reason to believe that recent earthquakes are warning signs of an imminent eruption. This simply means that this is a place where researchers may want to pay more attention.
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