Science Pick of the Week: Visiting geologist discusses the inner workings of Mt. St. Helens ahead of talk at MNCH
Hawaii’s Kilauea volcano drew headlines following its recent eruption on Friday. But the Pacific Northwest is a hotbed for geologic activity, too. The Channeled Scablands of Eastern Washington, the John Day Fossil Beds of Eastern Oregon and the Columbia Gorge are emblematic of the region’s tumultuous geologic history. Mount St. Helens, however, is probably the landmark that first comes to people’s minds given its eruption in 1980.
The eruption attracted droves of earth scientists to research the active volcano. Nearly 40 years later, scientists such as Dr. Brandon Schmandt, a geophysicist and seismologist at the University of New Mexico, are able to accurately map the inner workings of the volcano. Dr. Schmandt will present the findings he and his colleagues discovered about the “magmatic plumbing” beneath the volcano. The talk is on Tuesday, May 7, at 3 p.m. at the Museum of Natural and Cultural History.
“If you went around the perimeter of the Pacific [Ocean], you could find many volcanic systems that have a lot of similar attributes to [Mt.] St. Helens,” Schmandt told the Emerald. “Why it stands out and why it’s been a focus lately is simply that it’s most active volcano in the Pacific Northwest and there are a lot of people who live near it.”
Mount St. Helens and the entire Cascade mountain range is a product of the Cascadia Subduction Zone. This is an area off the Oregon-Washington coast, beneath the ocean, where the Juan de Fuca plate is sliding under the larger North America continental plate. Besides generating earthquake-producing friction, the sliding Juan de Fuca plate pulls water, sediment and various reactive minerals with it; an explosive combination for volcanoes.
“Those are things that we would see at the surface normally but [the plate movement] drags them to depths where they’re not stable,” Schmandt said. “Those end up lowering the melting point of the mantle. Then the melt that’s created by that sinking flap rises up under the overriding plate — the overriding plate being what you guys live on.”
While Schmandt said scientists cannot forecast eruptions, volcanoes will give off warning signs, such as steam venting or small lava flows. But these signs are sometimes red herrings.
“I think we would see indicators ahead of time if St. Helens were to start ramping up toward a new eruption,” he said. “We’re not seeing those indicators — at least not very strong ones right now.”
Schmandt was selected to participate in the National Science Foundation program GeoPRISMS, which brings together earth scientists from different disciplines to examine a specific area of the world. A few years back, the Cascadia Subduction Zone was chosen as a site of interest. Schmandt hopes his research on Mount St. Helens, combined with his colleges’ work on other areas of the subduction zone could provide a case study for examining other volcanic regions in the world.
“What we learn will be important regionally because it is a very active volcano in the Pacific Northwest,” Schmandt said. “But it’s also applicable more broadly because there are tons of volcanoes that are very similar in many respects to Mount St. Helens.”
As for the lecture, Schmandt wants to provide attendees with a modern view of Mount St. Helens and where it fits into global volcanic processes and hazards.
“We have a great depth of information,” Schmandt said. “In a way [Mount St. Helens] is a place to sort of keep doubling down and say, ‘Well, let’s zoom in more and more,’ because these are pretty complex systems.”
Dr. Schmandt’s lecture will begin at 3 p.m. in the Museum of Natural and Cultural History Galleria on Tuesday, May 7. The talk is included with regular museum admission, free for UO students.
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