Increased Seismic Activity Recorded at Mount Adams Volcano Without Eruption Threat

Mount Adams in Southwest Washington experienced six low-intensity earthquakes in September, marking the highest monthly activity since 1982. Although these quakes were small and posed no immediate eruption threat, monitoring efforts are being enhanced to ensure community safety and preparedness.

Recent seismic activity has been recorded beneath Mount Adams, a prominent volcano located in Southwest Washington, with the U.S. Geological Survey Cascades Volcano Observatory reporting six low-intensity earthquakes occurring in September. This unusual uptick in seismic events marks the highest monthly earthquake count observed since monitoring of Mount Adams began in 1982. Despite the increased activity, officials have expressed that there is currently no imminent threat of an eruption, noting that the last recorded eruption of Mount Adams took place between 3,800 and 7,600 years ago. The earthquakes detected ranged in magnitude from 0.9 to 2.0, and according to geologist Holly Weiss-Racine of the Volcano Observatory, these quakes are considered “extremely small” and would have been imperceptible to the local population. Historically, Mount Adams averages one earthquake every two or three years, and while the increase in seismic events this past September is notable, Weiss-Racine commented that it does not signify any alarming trends. There are specific indicators that can suggest a volcano is becoming active, such as a significant rise in earthquake frequency, ground deformation, or increased gas emissions. However, Weiss-Racine reassured that, “Right now, we’re not seeing any of those things. We’re just seeing these six earthquakes.” In terms of its potential eruption, Mount Adams is characterized as less explosive compared to its neighboring Mount St. Helens, which experienced a devastating eruption in 1980. Mount Adams is more likely to produce thick, sticky lava flows rather than volcanic ash, although lahars—mixture of volcanic material and melted snow—remain a serious concern during even small-scale eruptions, posing risks to nearby communities such as Trout Lake in Klickitat County. The current seismic activity appears concentrated beneath the mountain’s center. However, the determination of precise epicenter locations and depths is complicated due to the limited monitoring infrastructure, with only one seismic station located seven miles southwest of the summit. To enhance monitoring efforts, the Cascades Volcano Observatory has temporarily installed an additional seismic station at a nearby trailhead and plans to add two more in the future. Legislation passed in 2019 authorized the establishment of a more comprehensive volcano monitoring system, and the U.S. Geological Survey is striving to implement four additional monitoring sites at Mount Adams with the necessary funding. As the process requires permits from the U.S. Forest Service, the installation of these advanced instruments may be delayed until next year due to imminent winter weather conditions. Weiss-Racine indicated that approvals from the Forest Service could be completed within the next month, but weather complications may hinder the installation timeline.

Mount Adams, with an elevation of 12,276 feet, is one of the dominant volcanic structures in the Cascade Range of Southwest Washington. The area is under constant observation by the U.S. Geological Survey (USGS) for seismic activity, as fluctuations can often indicate changes in volcanic behavior. Although past eruptions of Mount Adams have occurred thousands of years ago, monitoring efforts have increased due to the potential hazards associated with volcanic eruptions, including explosive activity and lahar occurrences. The installation of additional monitoring stations is critical for a comprehensive understanding of the volcano’s activity and for community preparedness.

In summary, while the recent increase in seismic activity at Mount Adams is noteworthy, officials assure that there is no immediate danger of an eruption. The earthquakes recorded in September are relatively minor and typical for volcanic regions. Ongoing efforts by the USGS and local authorities aim to enhance monitoring capabilities for the safety of nearby communities. Future improvements to surveillance infrastructure are anticipated as the Forest Service processes permit applications.

Original Source: www.seattletimes.com