Mount Adams in Southwest Washington experienced six low-intensity earthquakes in September, marking the highest monthly count since monitoring began in 1982. Despite the unusual seismic activity, experts assert there is no immediate eruption threat. Monitoring efforts are being enhanced to better track volcanic activity.
Recent seismic activity beneath Mount Adams in Southwest Washington has raised some attention, as the U.S. Geological Survey’s Cascades Volcano Observatory reported six low-intensity earthquakes occurring in September. This marked an unusual spike in seismic activity, being the highest monthly count since monitoring began in 1982. However, officials assure there is no immediate threat of an eruption, given that Mount Adams last erupted between 3,800 and 7,600 years ago. The earthquakes detected had magnitudes ranging from 0.9 to 2.0, described by geologist Holly Weiss-Racine as “extremely small,” indicating that residents likely did not feel them. Historically, the volcano experiences approximately one earthquake every two to three years; therefore, the recent increase is noted as intriguing but not alarming. Weiss-Racine elaborated on indicators that typically signal a volcano might be entering a phase of unrest, which include substantial earthquakes, ground deformation, and increased gas emissions. However, she emphasized, “Right now, we’re not seeing any of those things. We’re just seeing these six earthquakes.” Volcanic activity can vary significantly, and while Mount Rainier, for example, may encounter small quakes daily, Mount Adams has shown similar variability. Should an eruption occur at Mount Adams—historically less explosive than its neighboring Mount St. Helens—it would likely result in lava flows rather than dangerous ash clouds. This characteristic is a product of the volcano’s geological composition, which accounts for its large volume within the Cascade Range. Nevertheless, lahars, or volcanic mudflows generated from melting ice and slurry, pose a significant risk in the event of an eruption, particularly as they could threaten populated areas such as Trout Lake in Klickitat County. The recent quakes originated beneath the volcano’s center. However, with only one monitoring station situated seven miles southwest of the summit, accurately determining the precise locations and depths of the seismic events remains challenging. In an effort to enhance monitoring capabilities, the Cascades Volcano Observatory has temporarily installed an additional seismic station at a local trailhead and plans to install two more. Congress authorized a comprehensive volcano early warning and monitoring system in 2019, and the USGS is currently working to install four new monitoring sites at Mount Adams, awaiting necessary permits from the U.S. Forest Service. The implementation of these more sophisticated monitoring instruments is expected, but adverse weather conditions may delay the installation until next year.
Mount Adams, a stratovolcano located in Southwest Washington, stands at 12,276 feet and has not erupted in several millennia, with the last confirmed eruption occurring between 3,800 and 7,600 years ago. Despite sporadic seismic activity, it has been largely dormant relative to its more active neighbors in the Cascade Range. The recent earthquake detection is unprecedented since systematic monitoring began in 1982, prompting geological caution but no immediate alert regarding volcanic eruption potential. Geologists continue to study volcanic behavior, which includes indicators of unrest such as increased seismic activity and gas emissions.
In summary, while six low-intensity earthquakes beneath Mount Adams in September have generated attention, officials maintain that there is no imminent threat of an eruption. The recent seismic activity, although notable as the highest monthly count in over four decades of monitoring, does not indicate significant volcanic unrest. Increased monitoring efforts are underway to ensure proper oversight of potential volcanic activity, which remains a vital component of public safety.
Original Source: www.seattletimes.com
