SALT LAKE CITY – University of Utah researchers say an unusual sequence of earthquakes in central Utah in 2018 and 2019 is reminiscent of ancient Utah volcanoes in the area. Luckily, they say there are no signs of an impending eruption.
The research, first published in Geophysical Research Letters last month, centered around a couple of quake-quake sequences in the Black Rock Desert near Fillmore. One of the earthquakes in central Utah occurred on September 12, 2018 and the other on April 14, 2019. The earthquakes recorded a magnitude of 4.0 and 4.1 respectively and produced several aftershocks.
The two earthquakes located the Black Rock Desert Volcanic Field, located in central Utah, between I-15 and the Utah-Nevada State Line. The volcanic area last erupted about 720 years ago, causing basalt ash cones and flows through Ice Springs, according to the U.S. Geological Survey.
In addition to the earthquakes detected by the Utah Regional Seismic Network, they were captured by temporary seismic equipment that was used less than 20 miles from the desert to control a geothermal well for a different project.
A team of researchers from the University of Utah, USGS, and the University of Iowa began work analyzing the data. The temporary team helped detect 35 aftershocks after the 2019 earthquake, nearly double what the normal system detected.
They found that the earthquake was 1½ miles below the surface, which is quite shallow for earthquakes. For example, the 5.7-magnitude earthquake that shook the Wasatch Front last year happened about 6 kilometers below the earth’s surface; the 2018 and 2019 earthquakes in central Utah were unrelated to the Magna earthquake, the largest in Utah since 1992.
In addition, earthquakes did not produce “cutting waves,” which are common in earthquakes in Utah. The frequency of seismic energy was also much lower than that of typical Utah earthquakes, Maria Mesimeri, a postdoctoral researcher at the University of Utah’s seismograph stations and lead author of the study, said Tuesday in a press release. ‘study.
“Because these earthquakes were so shallow, we could measure surface deformation (due to earthquakes) using satellites, which is very unusual for such small earthquakes,” he said.
The data led researchers to believe that the earthquakes were not caused by fault collisions like most Utah earthquakes; rather, they said their research indicated that these earthquakes were the result of ongoing activity in the volcanic field beneath the desert.
Mesimeri said it is likely that both earthquakes could have been caused by magma or hot water that approached the surface and caused the earthquakes.
“Our findings suggest that the system remains active and that the earthquakes were probably the result of a fluid-related movement in the general area,” he said. “Earthquakes could be the result of the extraction of fluid through the rock or the result of the deformation of the movement of the fluid that highlighted the surface faults.”
The good news, he added, is that there is no reason to believe recent earthquakes are warning signs of an impending eruption. It just means it’s a place where researchers may want to pay more attention.