How recently discovered giant magma 'cap' helps prevent eruption at Yellowstone National Park
As part of their study, scientists used a 53,000-pound truck usually used for oil and gas exploration to send seismic waves into the ground at Yellowstone.
FILE: Hydrothermal explosion rocks tourists at Yellowstone National Park
A hydrothermal feature inside Yellowstone National Park sent rocks and debris flying, damaging a pedestrian boardwalk and forcing the closure of the area.
MAMMOTH SPRINGS, Wyo. – Scientists found that a "cap" made of a supercritical fluid and magma stands between the magma reservoir underneath Yellowstone National Park and a volcanic eruption.
In a recent article published in Nature, researchers were able to make this determination when they pinpointed the depth of the top of the reservoir for the first time, according to lead author Chenglong Duan.
Duan and his team found the depth where the reservoir began by using a 53,000-pound vibroseis truck, a vehicle usually used for oil and gas exploration, to send seismic waves into the ground in Yellowstone. They then used more than 600 seismometers to record the signals from the truck.
The truck used to send seismic waves. (Brandon Schmandt / Rice University / FOX Weather)
Based on the seismic readings, the research team determined that the reservoir began at just over 2 miles beneath the surface.
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"The motivation behind my research is to advance structural seismic imaging beyond the limits of conventional travel-time methods," said Duan, a postdoctoral research associate in the Department of Earth, Environmental and Planetary Sciences at Rice University. "Using a wave-equation imaging technique I developed during my Ph.D. for irregular seismic data, we made one of the first super clear images of the top of the magma reservoir beneath Yellowstone caldera."
That image is featured below, with the magma reservoir cap noted with a black arrow.
Graphic showing location of the subsurface cap. (Chenglong Duan / Rice University / FOX Weather)
The research team also noticed something curious about the top of the reservoir.
"Seeing such a strong reflector at that depth was a surprise," said co-author and Rice University Earth, Environmental and Planetary Sciences professor Brandon Schmandt. "It tells us that something physically distinct is happening there — likely a buildup of partially molten rock interspersed with gas bubbles."
More accurately called "supercritical fluid" for their unique state in the magma chamber, Schmandt noted that those bubbles formed when volatiles, or small fractions of elements like hydrogen, carbon and sulfur, in the magma are released in the upper areas of the chamber.
One of the more than 600 seismometers used to record the vibroseis truck signals. (Brandon Schmandt / Rice University / FOX Weather)
He likened the phenomenon to a soda can, which has bubbles that are dissolved in the liquid. When the can is opened, the bubbles come out of the liquid and rise to the top of the can.
But also like the bubbles in a pressurized soda can, the bubbles dissolved in the magma underneath Yellowstone have the potential to build up and lead to a volcanic eruption.
However, researchers found that, in addition to the bubbles rising to the top of the magma chamber, the peculiar geology in the national park is preventing that from occurring. Schmandt noted that the park’s systems of hydrothermal features provide passageways for the bubbles to escape the magma chamber and reduce the amount of pressure in the chamber.
General views of Crackling Lake in the Norris Geyser Basin at Yellowstone National Park on May 27, 2021 in Yellowstone National Park, Wyoming. (AaronP/Bauer-Griffin/GC Images / Getty Images)
"Yellowstone's magma reservoir is a lively system that is not very far from the surface, just about 2 miles deep, and bubbles are rising through it," he said. "It's remarkable that we can get detailed information about the subsurface without directly breaking ground, and that technology is important for studying natural hazards and resources."