OurAmazingPlanet Staff
Date: 11 April 2011 Time: 04:34 PM ET
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The volcanic plume of partly molten rock that feeds the Yellowstone supervolcano. Yellow and red indicate higher conductivity, green and blue indicate lower conductivity. Made by University of  CREDIT: University of Utah. |
The gigantic underground plume of partly molten rock that feeds the Yellowstone supervolcano might be bigger than previously thought, a new image suggests.
The study says nothing about the chances of a cataclysmic 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, the last of which occurred more than 600,000 years ago. [Related: Infographic - The Geology of Yellowstone.]
Earlier measurements of the plume were produced by using seismic waves — the waves generated by earthquakes — to create a picture of the underground region. The new picture was produced by examining the Yellowstone plume's electrical conductivity, which is generated by molten silicate rocks and hot briny water that is naturally present and mixed in with partly molten rock.
"It’s a totally new and different way of imaging and looking at the volcanic roots of Yellowstone," said study co-author Robert B. Smith, professor emeritus and research professor of geophysics at the University of Utah, and a coordinating scientist of the Yellowstone Volcano Observatory.
Ancient eruptions
Almost 17 million years ago, the deep plume of partly molten rock known as the Yellowstone hot spot first breached the surface in an eruption near what is now the Oregon-Idaho-Nevada border.
As North America drifted slowly southwest over the hot spot, there were more than 140 gargantuan caldera eruptions — the largest kind of eruption on Earth — along a northeast-trending path that is now Idaho's Snake River Plain.
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