Record Quakes at Mount Adams Prompt Urgent Volcano Monitoring in Washington State.

Mount Adams over Hood River Valley.Photo byDavid Gn

Researchers are urgently seeking answers after a significant series of earthquakes rattled Mount Adams Volcano, the largest active volcano in Washington state. The United States Geological Survey (USGS) reported six earthquakes striking the 'high threat' volcano in September, marking the highest number of earthquakes ever recorded in a single month since records began in 1982. This is a stark contrast to the typical occurrence of 1 earthquake every 2-3 years at this volcano. 

Mount Adams last erupted between 3,800 and 7,600 years ago. Since then, the volcano has produced ‘effusive eruptions,’ which produce slow morning lava flows, as opposed to the destructive ‘explosive eruptions’ we are primarily familiar with.

While the recent earthquakes at Mount Adams do not necessarily indicate an imminent eruption, the need for improved monitoring is crucial. The alert level and color code for Mount Adams remain at GREEN / NORMAL, as reported by the USGS. However, the current monitoring capabilities are limited, with just one seismic station near the volcano. Recognizing this, CVO has obtained permission from the U.S. Forest Service to install temporary seismic stations south and southwest of Mount Adams, a crucial step in enhancing our seismic monitoring capabilities.

Hazards Summary for Mount Adams.Photo byUSGS

Mount Adams is the second-tallest volcano in Washington State. The nearest major cities are Yakima, 50 miles to the northeast, and the Portland metropolitan area, 60 miles to the southwest. It is the state's largest active volcano in terms of area and volume, having formed around 520,000 years ago. The greatest danger to people living near Mount Adams is lahars, which could occur during eruptive or noneruptive periods. These muddy flows of rock, ash, and ice surge downstream like rapidly flowing concrete.

CVO and PNSN scientists will start monitoring data from the temporary seismic stations, which, along with information from the permanent station, will allow them to find more minor earthquakes and understand the cause of the recent events.