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.