‘Unusual’ six small earthquakes recorded at Mount Adams, monitoring efforts to increase

In September, six small earthquakes were detected at Mount Adams, according to the U.S. Geological Survey Cascades Volcano Observatory (CVO) and Pacific Northwest Seismic Network (PNSN).

The quakes, which ranged in magnitude from 0.9 to 2.0, are unusual for the volcano, where only one earthquake is typically recorded every two to three years.

Despite this increase in activity, officials report no cause for concern, and the volcano’s alert level remains at GREEN / NORMAL.

The earthquakes were detected by a seismic station located about seven miles southwest of the summit, and while none of the tremors were felt at the surface, this represents the highest number of quakes recorded at Mount Adams in a single month since monitoring began in 1982.

With only one seismic station near the volcano, monitoring capabilities are limited, but CVO and PNSN are planning to install temporary seismic stations to improve data collection.

These new stations will help detect smaller quakes and provide better estimates of their size, location, and depth.

Satellite imagery has not shown any signs of ground deformation, and there is no volcanic gas sampling program in place at Mount Adams.

The increased seismic monitoring will assist in determining the cause of the earthquakes and whether any additional actions are needed.

Mount Adams, located about 50 miles west of Yakima, is the second-tallest volcano in Washington and the state’s largest active volcano by area and volume.

Its historical eruptions have been mostly lava flows, with little explosive activity.

The primary threat from the volcano is lahars—destructive mudflows that could occur during or between eruptions.

The USGS has ranked Mount Adams as a high-threat volcano, and the agency is working to enhance monitoring systems at high- and very-high-threat volcanoes across the Cascade Range as part of the National Volcano Early Warning System.

©2024 Cox Media Group