After increased seismic activity, lawmakers seek additional information on Mount Adams

Nov. 1—Two members of Congress whose districts straddle Mount Adams have written a letter urging the U.S. Geological Survey (USGS) to enhance seismic monitoring of volcanoes across the country.

The letter, sent by U.S. Reps. Marie Gluesenkamp Perez, D-Skamania, and Dan Newhouse, R-Sunnyside, comes after the USGS reported a recent increase in seismic activity at the mountain.

A part of the Cascade Volcanic Arc, which includes Mount Rainier and Mount St. Helens, Mount Adams is located 50 miles southwest of Yakima and 30 miles north of the White Salmon-Hood River area along the Columbia River.

At 12,277 feet tall, it is the second tallest active volcano in Washington state behind Mount Rainier, and the largest by area and volume. According to the USGS, Mount Adams last erupted between 3,800 and 7,600 years ago.

"Any surge in seismic activity heightens our community's concern about larger earthquakes and volcanic activity, and the potentially devastating impacts to families and vulnerable infrastructure like the structurally deficient I-5 Bridge. It is critical that USGS take these concerns seriously, answer our communities' questions, and enhance monitoring of volcanoes across the Pacific Northwest," Reps. Gluesenkamp Perez and Newhouse wrote. "Though USGS has assured us that there's no cause for concern, our community understandably has questions about the increase in seismic activity, the threat level, and the status of USGS volcano monitoring across the Pacific Northwest."

In September, a seismic station near the volcano recorded six earthquakes between magnitude 0.9 and 2.0. The earthquakes were the most activity recorded at Mount Adams in any month since monitoring began in 1982.

Following the activity, the USGS Cascades Volcano Observatory and the Pacific Northwest Seismic Network installed additional temporary seismic stations to the south and southwest of Mount Adams, according to previous reporting by The Chronicle.

Despite the increased activity, the USGS volcano alert level for Mount Adams remains at its lowest level — green, or normal.

In the letter, the lawmakers requested additional information from the USGS, including the number of seismic stations around Mount Adams, the length of time the agency plans to operate temporary stations and whether the agency has enhanced at other volcanoes in the region.

"It is critical that USGS take these concerns seriously, answer our communities' questions and enhance monitoring of volcanoes across the Pacific Northwest," the letter states.