Magma Cap Discovered Beneath Yellowstone May Help Prevent Eruption With ‘Steady Breathing’

A team of researchers discovered a magma cap beneath the surface of Yellowstone National Park that actually works to prevent the eruption of the massive volcanic system.

The study, led by Rice Universitys Chenglong Duan and Brandon Schmandt along with collaborators from the University of New Mexico, University of Utah and the University of Texas at Dallas, was published in the journal Nature, and details the discovery of a magma “cap” 3.8 km, or about 2.4 miles, beneath the surface.

The magma cap traps heat and pressure below it, but the reservoir remains stable because it is actively releasing gas through vents found throughout the park.

“For decades, weve known theres magma beneath Yellowstone, but the exact depth and structure of its upper boundary has been a big question,” said Schmandt, professor of Earth, environmental and planetary sciences. “What weve found is that this reservoir hasnt shut down — its been sitting there for a couple million years, but its still dynamic.”

Previous studies estimated the depth of the magma system as between 3 and 8 km deep, but the latest study used a high-resolution seismic survey in the northeastern part of the caldera to pinpoint the depth. The survey utilized a 53,000-pound vibroseis truck, which is generally used for oil and gas exploration, to produce tiny earthquakes, sending seismic waves into the ground to measure subsurface layers.

“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. “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.”

The data revealed there were likely gas bubbles interspersed with partially molten rock. After modeling various rock, melt and volatile combinations, researchers concluded the magma cap is a volatile-rich mixture of silicate melt and supercritical water bubbles within a porous rock matrix.

But the bubbles aren’t accumulating and driving explosive eruptions, as would normally be expected. Instead, they are being released continuously, preventing eruption.

“Although we detected a volatile-rich layer, its bubble and melt contents are below the levels typically associated with imminent eruption,” Schmandt said. “Instead, it looks like the system is efficiently venting gas through cracks and channels between mineral crystals, which makes sense to me given Yellowstones abundant hydrothermal features emitting magmatic gases.”

Schmandt likened the process to “steady breathing,” offering scientists a better way to monitor the volcano’s activity.

The data wasn’t easy to analyze, because Yellowstone’s unique geology is known for scattering seismic waves, according to Duan.

“When you see noisy, challenging data, dont give up,” Duan said. “After we realized the standard processing was not going to work, thats when we got creative and adapted our approach.”

Along with offering a roadmap for better predicting Yellowstone’s volcanic activity, the study provides insight into other subsurface imaging applications such as for carbon storage and energy exploration.

“Being able to image whats happening underground is important for everything from geothermal energy to storing carbon dioxide,” Schmandt said. “This work shows that with creativity and perseverance, we can see through complicated data and reveal whats happening beneath our feet.”