A new research deciphers magmatic structure and movements underneath the Yellowstone. The finding can advance the creation of systems that could predict the timing of future eruptions.
While the new discovery does not help in identifying the precise schedule of when the next Yellowstone eruption would be, it identifies what fueled the eruptions in the past. Specifically, the scientists decipher the structure of the magmatic plumbing system underneath the supervolcano where this magma originates and how they move and accumulate.
What Triggers Yellowstone Explosions?
The last Yellowstone caldera-forming eruption occurred 630,000 years ago, while the largest volume of lava surfaced 70,000 years ago.
With the use of computer modeling, scientists from the University of Oregon identified the presence of thick crustal layer underneath the Yellowstone. This layer may control the movement of magma and propel its surfacing from the Earth's mantle until eventually spewed out from the volcano's mouth as lava.
Within 3 to 6 miles deep of the volcano is the upper crust layer consisting of cold and hard rocks. This is also where opposing forces take place. As the forces fight against each other, the pressure will open up paths where hot, ductile, and partially molten rock underneath can find its way into the upper crust.
These paths can trap magmas, causing them to accumulate and solidify in a large horizontal body called a sill. The accumulating magma can build up a sill of as much as 9 miles thick. Even at this depth, the sill could only fill up the mid-crustal part of the volcano. Above the mid-crustal part is another form of magma bodies that contains the gas-rich rhyolitic magma.
"We think that this structure is what causes the rhyolite-basalt volcanism throughout the Yellowstone hotspot, including supervolcanic eruptions," says Ilya Bindeman, coauthor and professor in the university's Department of Earth Sciences.
The structure of the sill and the mid-crustal layer projected in the computer modeling are similar with other supervolcanoes that erupted around the world, explains Dylan Colón, the lead researcher for the study.
Predicting Future Yellowstone Eruptions
The research, which was published in full in Geophysical Research Letters, can be used to compare the mantle plumes underneath Yellowstone and mantle plumes found in other supervolcanoes. By comparing, experts could soon predict the actual situation at Yellowstone, Colón says.
Colón, however, clarifies that the computer models of the seismic images could not identify the exact composition, state, and amount of magma that lie above and below the sill. The images could not also explain why and how they formed there.