From Discover Magazine- “Wilderness vs. Monitoring: The Controversy of a New Seismic Network at Glacier Peak”


From Discover Magazine

August 19, 2018
Erik Klemetti

Glacier Peak in Washington. Wikimedia Commons.

One of the most potentially dangerous volcanoes in the Cascades is Glacier Peak in Washington. It produced the one of the largest eruptions in the past 20,000 years in this volcanic range that spans from British Columbia to California. Multiple eruptions around 13,500 years ago spread ash all the way into Montana. Over the last 2,000 years, there have been multiple explosive eruptions that have impacted what became Washington state and beyond. Put on top of that the many glaciers on the slopes of Glacier Peak that could help form volcanic mudflows (lahars) during a new eruption, and you can see that Glacier Peak is a real threat.

Yet, even with this hazard posed by the volcano, there is very little in the way of monitoring equipment on the volcano. Currently, there is a lone seismometer on the volcano to measure earthquakes, one of the most important pieces of information needed to monitor volcanoes.

The lone seismometer at Glacier Peak. USGS.

A single seismometer is better than no seismometer, but it can only give us so much information. Without a network of at least 3 seismometers (a“seismic network”), we can really only measure if earthquakes are occurring at the volcano and not exactly where and how far beneath the volcano the temblors are happening. This is what is installed at a truly restless volcano like Mount St. Helens.

These two pieces of information — location and depth — are vital for understanding what might be happening at the Glacier Peak if any earthquake swarm were to happen. Otherwise, we might have difficulty differentiating between earthquakes happening due to fault motion near the volcano or shallow changes in the hydrothermal system in the volcano rather than magma moving into the volcano from deep below.

So, it might seem to be a no-brainer that new USGS seismic stations should be set up on Glacier Peak. However, that’s where things get messy. Glacier Peak is within designated US Forest Service Wilderness area, so modification and use of the land are very tightly regulated and restricted. This is rightly so — we need to protect our wilderness from encroaching development or resource exploitation by people who don’t value a wild America.

The problem becomes that a seismic station, a fairly small installation that might have a 3 by 3 meter footprint, still disrupts wilderness in order to build the station as it requires the seismometer to be buried and secured to a stable platform (like rock or poured concrete). Additionally, although many stations are solar, they do require back-up batteries that need to be changed … and if there are no roads and trails in the wilderness, getting material to the station is next to impossible.

In order to perform repairs and resupply batteries, helicopters will be needed, so ideally, a helicopter pad near the seismic stations is needed for safe operation. This is a bigger deal as a helicopter pad might take up a few hundred square meters. It is this sort of disruption that has the Wilderness Watch speaking out against the installation of new seismic stations at Glacier Peak.

See the full article here .


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