Monitoring Cascade Magma


By Tanya Silverman

A view of Mt Hood. Photo coutesy of John Fowler.

Oregon’s Mt Hood is revered for many reasons. The iconic snow-capped formation holds the title as the state’s highest peak and acts as a majestic eastern backdrop to the urban bounds of Portland. Mt Hood is also recognized for its extensive forest, as well as its various facilities for skiing, camping, hiking, and plenty of other outdoor activities. Additionally, Mt Hood’s Timberline Lodge was famously featured in Stanley Kurbick’s The Shining.

But beyond all of the natural beauty, athletic endeavors, and cultural references, there is a grave geologic factor that must be acknowledged about Mt Hood: it is an active stratovolcano.

Consequently, the Cascades Volcano Observatory (CVO) branch of the United States Geological Survey (USGS) made a proposal to install four stations on Mt Hood’s upper flanks in order to monitor volcanic activity. These unmanned stations would be set up in the wilderness area to gather GPS, volcanic gas, and seismic data. The CVO-USGS writes that Mt Hood “produces frequent earthquakes, and steam and volcanic gases are emitted in the area around Crater Rock near the summit.”

The USGS classified Mt Hood a “very high threat” after executing a 2005 survey. As USGS geologist Peter Cervelli explains on the phone from Alaska, the survey assessed potential dangers alongside nearby populations and infrastructures, as well as the types of instruments that were already in place.

Mt Hood is one of several active volcanoes of the Cascades Range in the Pacific Northwest. Others include Oregon’s Crater Lake, plus Washington’s Mt Rainier and Mt St Helens–all of which are considered to be high priorities for geological monitoring. Their potentially disruptive activity can be hazardous to the people residing in centers like Portland, Seattle, and Olympia. Nearby transportation systems, infrastructures, and air corridors are also threatened by volcanic activity.

Cervelli informs BTR that the Cascades volcanoes are unique because they are prone to producing lahars, which are muddy volcanic floods. The spur of a lahar may melt glaciers, thus picking up a mess of dirt and other matter as they flow downstream. The lahar’s flow can also dislodge boulders.

As a result of this danger, the USGS installs monitoring technology specifically purposed to screen lahars around the Cascades. These instruments are set up downstream from glaciers and are intended to provide early warning to nearby communities. Otherwise, Cervelli says, the Cascades have the same monitoring tools as volcanoes in places like Alaska and Hawaii.

Cervelli informs BTR that the Cascades volcanoes erupt often (in terms of geologic history) and explosively, a factor historically exhibited on May 18, 1980, by the Mt St Helens eruption. The disaster resulted in lahars, ashfall, and a lateral blast that killed 57 people. Two hundred homes were damaged or destroyed.

Carolyn Driedger, a Hydrologist/PIO/Outreach Coordinator at USGS-CVO based in Vancouver, Washington, witnessed the Mt St Helens eruption. She describes the disaster as a real “career changer” which transformed the lives of the people in the Pacific Northwest. Dreidger adds that the 1980 eruption also changed the way that scientists “do business.”

The Mt St Helens event became the 20th century’s most studied volcanic eruption, according to San Diego State University.

“Since that eruption, we have updated hazards assessments, worked in partnership with officials to develop and exercise emergency coordination plans, and have been methodically improving our monitoring systems, one volcano at a time,” Driedger says.

Today, Driedger educates locals about volcano eruption preparedness, teaching them how to evacuate, communicate, and prepare for potential disasters. She discourages people from becoming complacent and states that the most important concept she teaches to community members is that “everyone has a role in risk reduction.”

Driedger tells BTR that volcanic monitoring technologies have improved greatly since the 1980 eruption of Mt St Helens, so scientists are now able to examine the data with greater precision. Updating the monitoring systems at “nearby Mt Hood” will give scientists more time to detect hazards and warn public officials.

In essence, all of the proposed monitoring technology and preparation techniques that take place around the Cascades volcanoes are not about causing panic for the region’s population. As Driedger explains, the CVO-USGS cares to install such stations to “allow people to make emergency preparations after which they can get on with their lives, enjoying living and recreating” around Mt Hood.