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Aug. 6, 2020

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Three additional monitoring stations to be installed on Mount Hood

Instrumentation will measure earthquakes, detect surface deformation that could foretell a coming eruption

By , Columbian staff reporter
Published:

Three volcano monitoring stations are scheduled to be installed on Mount Hood next week in what the U.S. Geological Survey says will be a big step for protecting lives and property.

Seth Moran, scientist-in-charge at the Cascades Volcano Observatory in Vancouver, said the three early-detection and monitoring stations will have seismometers, used to measure earthquakes, and GPS receivers, used to detect surface deformation.

“If the ground starts moving, when magma is moving, it can deform the surface,” Moran said. “This will really give us capacity to detect ground deformation associated with unrest.”

The 1980 eruption of Mount St. Helens, the most active volcano in the Cascades, provides an example of how monitoring can foretell a coming eruption.

In March 1980, a series of earthquakes offered scientists the first clues that Mount St. Helens was waking, 123 years after its last major eruption in 1857.

In the days leading up to the cataclysmic eruption on May 18, 1980, a bulge on the volcano’s north side was growing by an astonishing 5 feet a day from magma moving and building below the surface.

According to the U.S. Geological Survey, Mount Hood has erupted repeatedly over millenniums, with its most recent eruptions occurring from 1781 to 1793.

The mountain is an active volcano that produces frequent earthquakes and earthquake swarms. Steam and volcanic gases are emitted around Crater Rock near the mountain’s summit.

Mount Hood has been classified as a “very high threat volcano,” in part because of its proximity to nearby communities.

Helicopter delivery

The early-detection and monitoring stations will be placed above Mount Hood’s treeline on the volcano’s west, north and east flanks. A volcanic gas monitoring station will be installed later.

A helicopter will be used to deliver equipment to the monitoring sites. About 15 employees from the Cascades Volcano Observatory will trek to the sites on foot to install the equipment.

Moran said it could take two full days, maybe three, to install the equipment at all three sites.

“You never know what complications you might be running into,” he said. “There are no motors up there. Everything will be done by hand.”

Poor weather could postpone installation because, as Moran noted, “helicopters need clear weather to fly.”

Minimizing effects

Installation of the three stations will come after five years of work with the U.S. Forest Service, which approved the project in August. The New York Times published a story last week about the long process to place volcanic instrumentation in wilderness areas on Oregon’s highest peak.

To minimize environmental effects, the stations will be positioned away from trails and painted to blend in with the area.

“Since the Department of the Interior is a steward of America’s public lands, one of our mandates is to ensure our scientific inquiries at USGS have as little impact on the landscape as possible,” USGS Director Jim Reilly said in a statement.

“Because this sensor network will have a relatively small footprint and we can access the data remotely from various locations, there will be very little disturbance to the environment and wildlife in this area. These stations represent a huge step forward in monitoring that helps us safeguard lives and property.”

‘Gold standard’

Once the three additional stations have been installed, there will be 11 seismometers and six GPS receivers on Mount Hood, Moran said.

Mount St. Helens, which he called “the gold standard” for volcano monitoring, has 20 stations within 10 miles.

Moran said a group of government and university scientists studied volcanos around the world and assessed what it takes to monitor a volcano before recommending 12 to 20 seismic and GPS stations within 10 miles.

“If Mount Hood were to wake up, would we be all set?” Moran asked. “And the answer is no. We would need to get more stations up there.”

Specifically, scientists would want to place a station on Mount Hood’s summit, which currently is difficult because of “brutal weather” at the top of the 11,249-foot mountain, Moran said.

“One way of thinking about our observatory is we are like a fire department in that we need to be ready for an eruption,” he said. “But unlike a fire department, we don’t have fires several times a day or several times a week.”

“Our job is to keep ourselves ready,” Moran added. “Part of that is taking seriously what we have seen around the world, and that is volcanos can wake up quickly.”

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