A seismology student from the University of Utah is claiming that the volume of molten magma beneath Yellowstone is 50% larger than previously thought. Given that the caldera could blow up at anytime and with little warning, that's a pretty scary thought.
Graduate student Jamie Farrell made the remarks yesterday (April 17) at the Seismological Society of America's annual meeting.
He was able to make the discovery by analyzing nearby earthquakes, whose waves change speed depending on whether they're propagating through molten or solid rock. This allowed Farrell to construct a picture of the enormous magma chamber beneath the park — one that now appears to be bigger and better connected than expected.
Writing in Our Amazing Planet, Beck Oskin reports:
The underground magma resembles a mutant banana, with a knobby, bulbous end poking up toward the northeast corner of Yellowstone National Park, and the rest of the tubular fruit angling shallowly southwest. It's a single connected chamber, about 37 miles (60 kilometers) long, 18 miles (30 km) wide, and 3 to 7 miles (5 to 12 km) deep.
Previously, researchers had thought the magma beneath Yellowstone was in separate blobs, not a continuous pocket.
The shallowest magma, in the northeast, also matches up with the park's most intense hydrothermal activity, Farrell said. The new study is the best view yet of this zone, which lies outside the youngest caldera rim.
The last caldera eruption at Yellowstone happened 640,000 years ago, but smaller eruptions have happened since then, including the most recent one roughly 70,000 years ago.
Read all of Oskin's report.
Top image: National Park Service.