2015-04-23. Two huge magma chambers spied beneath Yellowstone National Park.

posted Apr 25, 2015, 5:25 PM by Alan Gould
By Eric Hand, Science (AAAS). For GSS Energy Flow chapter 2. Excerpt: Underneath the bubbling geysers and hot springs of Yellowstone National Park in Wyoming sits a volcanic hot spot that has driven some of the largest eruptions on Earth. Geoscientists have now completely imaged the subterranean plumbing system and have found not just one, but two magma chambers underneath the giant volcano. “The main new thing is we unveil a deeper and bigger magma reservoir in the lower crust,” says study author Hsin-Hua Huang, a seismologist at the University of Utah in Salt Lake City. Scientists had already known about a plume, which brings molten rock up from deep in the mantle to a region about 60 kilometers below the surface. And they had also imaged a shallow magma chamber about 10 kilometers below the surface, containing about 10,000 cubic kilometers of molten material. But now they have found a deeper one, 4.5 times larger, that sits between 20 and 50 kilometers below the surface. ...The last major eruption was 640,000 years ago, and today the threat of earthquakes is far more likely. But the deeper chamber does mean that the shallow chamber can be replenished again and again. “Knowing that you have this additional reservoir tells you you could have a much bigger volume erupt over a relatively short time scale,” says co-author Victor Tsai, a geophysicist at the California Institute of Technology in Pasadena.  ...Huang says that with rough dimensions now in hand for all the major magma bodies, modelers can try to understand how magma moved around in past eruptions—and why the chambers sit where they are.... http://news.sciencemag.org/earth/2015/04/two-huge-magma-chambers-spied-beneath-yellowstone-national-park