A 3.1-magnitude seismic event rattled Utah on Wednesday evening, initially sparking questions about its cause before being identified by the U.S. Geological Survey (USGS) as an explosion at a nearby mining site.
The blast, equivalent to 1,500 pounds of TNT, was recorded at a depth of zero feet, indicating it occurred at the surface. The event took place outside Maeser, an area characterized by numerous mines and mining claims.
The USGS detected the seismic event at 4:59 p.m. ET. While the agency registered one report of shaking, individuals in nearby Vernal city limits, approximately nine miles from the epicenter, reported not feeling any tremor.
Mining explosions can generate seismic waves similar to those produced by natural earthquakes. However, a key distinction is that explosions typically happen at or near the surface, whereas earthquakes originate deeper underground from the rupture of rocks along faults.
It remains undetermined which specific mining operation was responsible for the blast or if it was a planned detonation. No injuries or damage have been reported in connection with the event.
This incident follows a similar manmade seismic event recorded off the coast of Florida just days prior. On Tuesday, the USGS detected a 3.9-magnitude tremor east of Flagler Beach, also noted with a zero-foot depth. The agency classified this event as an 'experimental explosion.' This location is approximately 20 miles from an area east of Ponce Inlet where the U.S. Navy is known to conduct Full Ship Shock Trials (FSST). These trials involve controlled underwater detonations to test the resilience of warships against battle-like explosions.
The USGS records such experimental explosions because its network of sensitive seismographs detects the ground vibrations they produce. Seismologists analyze these signals to differentiate between human-made blasts and natural earthquakes. These events are commonly associated with controlled military exercises, seismic research, and industrial mining operations.
Utah is situated in a region prone to seismic activity, home to over 200 active faults, including the Wasatch Fault Zone. Wednesday's explosion occurred about 171 miles east of Salt Lake City.