University of Utah scientists say seismic images of the plumbing feeding the Yellowstone supervolcano show a magma plume much larger than previously thought. Scientists say they've imaged a plume of hot and molten rock rising at an angle from the northwest at a depth of at least 410 miles, contradicting claims there is no deep plume, only shallow hot rock moving like slowly boiling soup. A related University of Utah study used gravity measurements to indicate the banana-shaped magma chamber of hot and molten rock a few miles beneath Yellowstone is 20 percent larger than previously believed, so a future...