September saw an increase in earthquake activity at Mount Adams, according to the U.S. Geological Survey (USGS) Cascades Volcano Observatory and the Pacific Northwest Seismic Network.
A total of six earthquakes ranging between 0.9 and 2.0 in magnitude were recorded on a seismic station near the Cascade stratovolcano last month. Previously, the station only recorded one earthquake every two to three years, according to USGS.
“This represents the most earthquakes located at Mount Adams in a month since monitoring began in 1982. No earthquakes were felt at the surface,” USGS stated. “The locations and depths are not well constrained due to the sparse Mount Adams seismic network, and smaller earthquakes have occurred that seismologists have been unable to locate.”
The Mount Adams seismic network only has a single seismic station about 7 miles southwest from the stratovolcano’s peak.
With the sharp increase in earthquake activity, though, the USGS Cascades Volcano Observatory and the Pacific Northwest Seismic Network are installing more temporary seismic stations to the south and southwest of Mount Adams.