Mount Adams

Mount Adams is a potentially active volcano located 50 km east of Mount St. Helens, and is the second highest peak in Washington State. Although it has not had a major eruption in 1,400 years, it is not considered extinct. Thermal anomalies and gas emissions at the summit indicate that Mount Adams is still active.

Except for Mount Shasta, Mount Adams is the largest volcano in the Cascades by volume. Nearly all of its eruptions have consisted of lava flows with little to no tephra. Parts of the main cone consist of rock weakened by hydrothermal alteration. There is potential for large landslides of this altered rock to generate mud flows and lahars that flow far down valleys.

There was a large debris flow avalanche in 1997 at Mount Admas that was well recorded seismically.

More information about Mount Adams from CVO

Background Seismicity

The PNSN operates 3 seismometers near Mount Adams. On average, we locate 3 earthquakes within 10 km of the volcano per decade.