Massive Magma Reservoir Found Under Yellowstone National Park

A new study released in the journal Science shows that magma exists beneath the subsurface of Yellowstone National Park.

It has long been suspected that magma exists throughout the extent of the Earth’s crust, and now seismologists at the University of Utah have found enough molten rock to fill 14 Grand Canyons. Geoscientists have completely imaged the subterranean in the National Park and discovered two magma chambers underneath the Yellowstone Volcano.

Photo Credit: Robert B. Smith and Lee J. Siegel

"For the first time, we have imaged the continuous volcanic plumbing system under Yellowstone," said first author Hsin-Hua Huang, also a postdoctoral researcher in geology and geophysics. "That includes the upper crustal magma chamber we have seen previously plus a lower crustal magma reservoir that has never been imaged before and that connects the upper chamber to the Yellowstone hotspot plume below."

The new discovery is 4.5 times larger than the one chamber scientists already knew about. Scientists were already aware of a plume which brings molten rock up to the surface, but now they have found a chamber between 20 and 50 kilometres below the Earth’s surface. But just because the discovery is there, that does not necessarily mean an eruption is imminent. The last major eruption in the area was 640,000 years ago.

University of Utah seismologists Fan Chi-Lin, Hsin-Hua Huang, Robert B. Smith and Jamie Farrell (Photo Credit: Lee J. Siegel, U of Utah)

“These findings do not increase the assessment of volcanic hazard for Yellowstone—the inferred magma storage region is no larger, the research simply makes a better image of the magmatic system. Simply, we have more key information about how the Yellowstone volcano works,” said the United States Geological Survey (USGS).

By looking at the data from thousands of earthquakes, scientists managed to discover the two magma reservoirs.

"The actual hazard is the same, but now we have a much better understanding of the complete crustal magma system," said study co-author Robert B. Smith, a research and emeritus professor of geology and geophysics at the University of Utah.

The study revealed a gigantic magma reseroir beneath the Yellowstone supervolcano (Photo Credit: Hsin-Hua Huang, U of Utah)

The three supervolcano eruptions at Yellowstone—on the Wyoming-Idaho-Montana border—covered much of North America in volcanic ash. A supervolcano eruption today would be cataclysmic, but Smith says the annual chance is one in 700,000. The three ancient Yellowstone supervolcano eruptions were only the latest in a series of more than 140 as the North American plate of Earth's crust and upper mantle moved southwest over the Yellowstone hotspot, starting 17 million years ago at the Oregon-Idaho-Nevada border. The hotspot eruptions progressed northeast before reaching Yellowstone two million years ago.