When we visited Yellowstone this summer, they told us we were on top of a volcano, but it's a little hard to believe until you see something like this.
Yellowstone Association E-Newsletter January 2010
Scientists have confirmed the existence of a magma plume under Yellowstone that fills a magma chamber 20 percent larger than previous estimates. Using a network of 150 seismographs that recorded seismic waves from earthquakes around the world as they passed over an area extending from Missoula, Montana, to Evanston, Wyoming, a team of scientists was able to create a first-of-its-kind three-dimensional image of the plume. Recent scientific debate has focused on whether volcanoes such as Yellowstone were created by magma plumes-fingers of molten rock rising from deep in the Earth-or from shallow pockets of magma. The research, which involved scientists from Utah, Massachusetts, Michigan, Norway, Taiwan, and Switzerland, not only confirms the existence of a plume, but also indicates it extends at least 500 miles into the Earth's mantle (the layer between the Earth's crust and its outer core). University of Utah professor emeritus of geophysics and Yellowstone Volcano Observatory scientist Dr. Robert Smith says the plume may go even deeper, perhaps originating from the core-mantle boundary some 1,800 miles deep.
Dr. Smith calls this latest research a major development in understanding how Yellowstone works-what happened in the past and what could happen in the future. He adds that these findings do not indicate that Yellowstone is on the verge of a major eruption, which he calls "a very rare thing." The region's last three major eruptions have taken place at intervals of about 700,000 years, with the last giant eruption occurring approximately 640,000 years ago.
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