Researchers from the University of Utah and the California Institute of Technology published the results of their study to map Yellowstone National Park’s Old Faithful Geyser in the journal Science on Thursday. They found a previously unknown magma chamber, which the Guardian reports holds enough molten rock to fill the Grand Canyon 11 times.
The team used seismic tomography, a sort of ultrasound technique, over five days in early April to map the ground underneath Yellowstone. According to the Guardian, scientists already knew of a large magma chamber. But this new one, holding 11,500 cubic miles of solid, spongelike, and molten rock, is 4.5 times bigger and sits 12 to 28 miles under the surface.
“The existence of the second magma chamber does not make it any more or less likely that a large volcanic eruption at Yellowstone will occur,” Jamie Farrell, a seismologist at the University of Utah, told the Guardian. “These findings do not change the current volcanic hazard at Yellowstone.” The last major eruption was 640,000 years ago, according to Science.
But this new discovery does mean that if Yellowstone’s hot spot were to blow its top, it would be a lot worse than previously thought. “Knowing that you have this additional reservoir tells you [that] you could have a much bigger volume erupt over a relatively short time scale,” Victor Tsai, co-author and geophysicist at CalTech, told Science.