It may not look like much, but the arid expanse of Utah hides an ancient volcanic complex, and this hidden underground system is still active far below the desert’s surface, scientists say.
According to a new study, a few recent earthquakes in 2018 and 2019 were not indicative of tectonic activity, but were the seismic rumbling produced by the Black Rock Desert volcanic field – an ancient volcanic system in Utah’s Sevier Desert that has already reached more than 6 million is active. years and is apparently still very much alive.
“Our findings suggest that the system is still active and that the earthquakes were likely the result of fluid-related motions in the general area,” said University of Utah seismologist Maria Mesimeri.
“The earthquakes could be the result of the fluid squeezing through rock or the result of deformation from fluid movements highlighting the surface defects.”
The two earthquake sequences in question took place in September 2018 and April 2019 and were recorded by seismometers within the Utah Regional Seismic Network, as well as by instruments that are part of an experimental project called Utah FORGE, led by the United States Department of Energy.
Later analysis of the waveforms from the episodes showed that these earthquakes were not the result of tectonic activity, with shallow signals coming from depths less than 2.5 kilometers (1.5 miles) below the surface.
“Seismic signals from these earthquakes were unusual and uncharacteristic of tectonic earthquakes, and we rule out the possibility of a mine collapse or explosion,” Mesimeri and her co-authors explain in their study.
“We confirm that the two earthquakes are shallow and that there is visible surface deformation.”
The evidence suggests that unlike other earthquakes in the area that stem from faulting movements and tend to produce more seismic energy, the shallow 2018 and 2019 events were caused by the transport of volcanic liquids within Black Rock’s volcanic field. , be it heated water or rocky water. magma.
Despite the volcanic complex’s ancient age, its tranquility in terms of apparent volcanic activity means it is a relatively little-known feature of Utah’s vast landscape. Black Rock’s last eruption was over 1,000 years ago, resulting in Ice Springs lava flows in the region.
As for whether the most recent rumble is indicative of future eruptions, there is no evidence for that, the researchers say. But these earthquakes remind us that Black Rock is still active after all these years and that this dormant volcano has not died out.
“The results showed that we need to pay more attention to the Black Rock area,” said Mesimeri.
“We need to improve seismic and volcanic monitoring in this area so that we are aware of small changes that may occur.”
The findings are reported in Geophysical Research Letters