Yellowstone’s electrical conductivity hints volcano plume is bigger than thought

 

WASHINGTON—Geophysicists have made the first large-scale picture of the electrical conductivity of the gigantic underground plume of hot and partly molten rock that feeds the Yellowstone supervolcano. The image suggests that the plume beneath the volcanically active area—renowned today for geysers and hot springs—is even bigger than it appears in earlier images made with earthquake waves.

“It’s like comparing ultrasound and MRI in the human body; they are different imaging technologies,” says geophysics Professor Michael Zhdanov of the University of Utah in Salt Lake City. Zhdanov is principal author of the new study and an expert on measuring magnetic and electrical fields on Earth’s surface to find oil, gas, minerals and geologic structures underground.

“It’s a totally new and different way of imaging and looking at the volcanic roots of Yellowstone,” says study co-author Robert B. Smith, professor emeritus and research professor of geophysics, also at University of Utah, and a coordinating scientist of the Yellowstone Volcano Observatory.

In the past 2 million years, three eruptions at Yellowstone have been huge, belching enough volcanic ash to cover half of North America. The new study says nothing about the chances of another cataclysmic caldera (giant crater) eruption at Yellowstone, but it provides scientists with a valuable, new perspective on the vast and deep reservoir of fiery material that feeds such eruptions.

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