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It may not sound like it, but Utah’s arid expanses hide an ancient volcanic complex, and this hidden underground system is still active well below the surface of the desert, scientists say.
According to a new study, a pair of recent earthquakes in 2018 and 2019 were not indicative of tectonic activity, but were seismic rumbles produced by the Black Rock Desert volcanic field – an ancient volcanic system in the desert. from Sevier of Utah who had been active for over 6 million people. years old and, apparently, is still alive.
“Our results suggest that the system is still active and that the earthquakes were likely the result of fluid-related movement in the general area,” says seismologist Maria Mesimeri of the University of Utah.
“Earthquakes could be the result of fluid crushing through rock or the result of deformation due to movement of the fluid that has stressed the surface faults.”
The two earthquake sequences in question occurred in September 2018 and April 2019, and were recorded by seismometers within the Utah Regional Seismic Network, as well as by instruments part of an experimental project called Utah FORGE, managed by the US Department of Energy.
Subsequent analysis of the waveforms of the episodes showed that these earthquakes were not the result of tectonic activity, with shallow signals emanating from depths less than 2.5 kilometers (1.5 miles) below the surface.
“The seismic signals from these earthquakes were unusual and unusual for tectonic earthquakes, and we rule out the possibility of a mine collapse or explosion,” Mesimeri and his co-authors explain in their study. .
“We confirm that both earthquakes are shallow and find a distinct surface deformation.”
Evidence suggests that unlike other earthquakes in the region which result from fault movements and tend to produce more seismic energy, the shallow events of 2018 and 2019 were produced by the transport of volcanic fluids. in the Black Rock volcanic field, be it heated water or rocky water. magma.
Despite the ancient age of the volcanic complex, its calm in terms of obvious volcanic activity makes it a relatively little-known feature of Utah’s great landscape. Black Rock’s last eruptive event dates back over 1,000 years, causing the area’s Ice Springs lava to flow.
As to whether the most recent rumblings indicate future explosions, there is no evidence for that, the researchers say. But these earthquakes are a reminder that Black Rock is still active after all these years and that this dormant volcano is not extinct.
“The results showed us that we should pay more attention to the Black Rock region,” says Mesimeri.
“We need to improve the seismic and volcanic monitoring in this area, so that we are aware of the small changes that may occur.”
The results are reported in Geophysical research letters.
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