Mount Adams in Southwest Washington experienced six low-magnitude earthquakes in September, the most in a month since monitoring began in 1982. While the seismic activity raised concerns, officials stated there is no immediate eruption threat. The monitoring network is set to expand to improve surveillance of the volcano.
In September, Mount Adams in Southwest Washington experienced a series of six low-magnitude earthquakes, as reported by the U.S. Geological Survey’s Cascades Volcano Observatory. These tremors, the highest recorded in a month since the monitoring of the volcano began in 1982, ranged in magnitude from 0.9 to 2.0, which geologist Holly Weiss-Racine characterized as “extremely small” and undetectable to residents in the vicinity. Historically, the volcano, which stands at 12,276 feet, typically registers only one earthquake every two or three years. Despite the uptick in seismic activity, officials have stated there is no imminent threat of an eruption, noting that the last eruption of Mount Adams occurred between 3,800 and 7,600 years ago. Weiss-Racine indicated that several key indicators, such as significant increases in seismic events, ground deformation, or heightened gas emissions, usually forecast a volcano entering a state of unrest. As of now, those indicators are absent, meaning that the recent earthquakes are not necessarily alarming. For reference, other regional volcanoes, such as Mount Rainier, may experience minor earthquakes daily. In the event of an eruption at Mount Adams, the geologic record suggests it would primarily generate viscous lava flows rather than the explosive ash emissions characteristic of Mount St. Helens’ 1980 eruption, which resulted in numerous fatalities and widespread ash fallout. However, lahars—mudflows generated by melted glacier ice mixing with volcanic debris—pose a significant risk, particularly to nearby populated areas like Trout Lake in Klickitat County. Although the recent seismic activity has been detected predominantly beneath Mount Adams, the existing monitoring infrastructure, limited to a single station located seven miles from the summit, hampers detailed analysis of the earthquakes’ precise locations and depths. To enhance monitoring capabilities, the Cascades Volcano Observatory has established a temporary seismic station and plans to add two more permanent stations. In 2019, Congress authorized a comprehensive volcano early warning and monitoring system. The U.S. Geological Survey is in the process of implementing four additional sites to provide more robust oversight of Mount Adams, pending necessary permits from the U.S. Forest Service, which may be granted within the next month. Installation of these new monitoring stations is projected to extend into the next year due to impending winter weather conditions.
Mount Adams, a prominent stratovolcano in the Cascade Range of Washington State, has a rich geological history characterized by both explosive and non-explosive eruptions. Geologists monitor the volcano closely due to its potential hazards, especially lahars and lava flows, which can affect local communities. This recent seismic activity, along with the established monitoring efforts, underscores the importance of understanding volcanic behavior and the necessity of thoughtful disaster preparedness in the region.
The recent seismic activity at Mount Adams, while notable as the most quakes in a single month since record-keeping began, does not currently indicate an impending eruption. The volcano’s monitoring efforts are set to strengthen with planned installations of additional seismic stations, which will enhance the ability to predict and respond to potential hazards.
Original Source: www.seattletimes.com
