It may not look like it, but the arid expanses of Utah hide an ancient volcanic complex, and this hidden underground system is still active far below the surface of the desert, scientists say.
According to a new study, a couple of recent earthquakes in 2018 and 2019 were not indicative of tectonic activity, but were seismic rumors produced by the volcanic field of the Black Rock Desert, an ancient volcanic system of the Sevier Desert of Utah that has been active for over 6 million years and apparently is still alive and standing.
“Our findings suggest that the system is still active and that the earthquakes were probably the result of a fluid-related movement in the general area,” says seismologist Maria Mesimeri of the University of Utah.
“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 two earthquake sequences in question occurred in September 2018 and April 2019 and were recorded by seismometers from the Utah Regional Seismic Network, as well as by instruments that were part of an experimental project called Utah FORGE , led by the U.S. 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 uncharacteristic of tectonic earthquakes and we rule out the possibility of a collapse or explosion of the mine,” Mesimeri and his co-authors explain in their study.
“We confirm that the two earthquakes are shallow and we find a distinguishable surface deformation.”
Evidence suggests that, unlike other earthquakes in the area that come from fault movements and tend to produce more seismic energy, the shallow events of 2018 and 2019 were caused by the transport of volcanic fluids within the volcanic field. of the Black Rock, either heated or rocky water. magma.
Despite the age of the volcanic complex, its tranquility in terms of obvious volcanic activity makes it a relatively little-known feature of the great Utah landscape. The last eruptive event in Black Rock took place more than 1,000 years ago, causing lava flow from the Ice Springs region.
According to researchers, if the latest rumors are indicative of future outbreaks, there is no evidence. But these earthquakes remind us that Black Rock is still active after all these years and that this latent volcano has not become extinct.
“The results showed us that we should pay more attention to the Black Rock area,” Mesimeri says.
“We need to improve seismic and volcanic surveillance in this area so that we are aware of the small changes that can occur.”
The findings are reported in Geophysical research letters.