A team of geoscientists from Rice University, University of New Mexico, University of Utah and the University of Texas at Dallas have discovered a sharp, volatile-rich magma cap beneath the surface of Yellowstone National Park that might be preventing a large explosion.
The cap, located 3.8 kilometers beneath the surface, acts like a lid trapping pressure and heat below it. With the help of innovative controlled-source seismic imaging and advanced computer model, the researches have found that the Yellowstone magma reservoir may be actively releasing gas while remaining in a stable state.
“For decades, we’ve known there’s magma beneath Yellowstone, but the exact depth and structure of its upper boundary has been a big question. What we’ve found is that this reservoir hasn’t shut down — it’s been sitting there for a couple million years, but it’s still dynamic.” – Brandon Schmandt, professor of Earth, environmental and planetary sciences at Rice University
Previous studies suggested that Yellowstone’s magma system could lie anywhere between 3 to 8 kilometers beneath the surface, but a a high-resolution seismic survey in the northeastern part of the caldera revealed a sharp boundary at about 3.8 km depth. Brandon Schmandt used a 53,000-pound vibroseis truck to create tiny earthquakes and send seismic waves into the ground. The waves reflected off subsurface layers and were recorded at the surface, revealing the magma system’s depth.
“Although we detected a volatile-rich layer, its bubble and melt contents are below the levels typically associated with imminent eruption. Instead, it looks like the system is efficiently venting gas through cracks and channels between mineral crystals, which makes sense to me given Yellowstone’s abundant hydrothermal features emitting magmatic gases.” – Brandon Schmandt
The system was likened to a steady breathing, slowly releasing bubbles through porous rock like a natural pressure-release valve and keeping the risk of eruption lower.
