Will Yellowstone Erupt Soon? Scientists Are Using New Techniques to Find Out

Each year, Yellowstone National Park attracts millions of visitors who are eager to see its explosive geysers, steaming hot springs and burbling mud pots. These famous natural landmarks result from the park’s unique geology: It sits atop an active supervolcano, which has produced three large, explosive eruptions in the last 2.1 million years.

The most recent eruption at Yellowstone took place roughly 70,000 years ago, when thick lava burbled up to the surface and flowed across the landscape. The last major explosion occurred around 631,000 years ago, creating a massive crater known as the Yellowstone Caldera.

Many curious onlookers have wondered whether—and when—Yellowstone might next erupt. Now, scientists are using new techniques to help answer these questions.

A new analysis published last week in the journal Nature suggests Yellowstone is unlikely to experience another big eruption—at least, not anytime soon—because the magma lurking beneath its surface is split across a web of distinct chambers.

Due to the large total amount of magma present, Yellowstone will remain volcanically active. But “nowhere in Yellowstone do we have regions that are capable of eruption,” says study lead author Ninfa Bennington, a seismologist at the U.S. Geological Survey’s Hawaiian Volcano Observatory, to the Washington Post’s Sarah Raza. “It has a lot of magma, but the magma is not connected enough.”

Past research has suggested a broad layer of magma exists beneath Yellowstone, but the new findings contradict that idea. “There are these segregated regions where magma is stored across Yellowstone, instead of having one sort of large reservoir,” Bennington adds to Fox Weather’s Angeli Gabriel.

Other studies have relied primarily upon seismic waves, which help map underground structures. Because seismic waves travel at different speeds through varying types of materials, scientists can use them to “see” what’s beneath Earth’s surface—such as a layer of solid rock or a chamber full of piping hot magma.

For this study, however, researchers used a technique called magnetotellurics. This method also allows researchers to “see” beneath the surface, but it uses Earth’s natural electromagnetic fields instead of seismic waves. Since magma is a good conductor of electricity, this technique is highly sensitive to mapping the molten rock, making it useful for understanding what’s happening underground at a volcanically active place.

Using magnetotellurics, scientists were able to produce a detailed picture of the magma beneath Yellowstone, which then allowed them to make predictions about possible future eruptions.

Their new map shows large, deep reservoirs of basaltic magma, which flows easily and is responsible for much of Earth’s volcanic activity. These chambers are connected to shallower underground pools of rhyolitic magma, which is thicker and requires more pressure to erupt, but tends to produce more explosive eruptions. The entire magma complex links into Yellowstone’s hydrothermal system, which is akin to underground plumbing near the surface.

Though basaltic eruptions are more common worldwide, the Yellowstone Caldera was formed by a rhyolitic eruption that launched magma with the same consistency as asphalt into the air, as Michael Manga, an Earth and planetary scientist at the University of California, Berkeley, who was not involved in the research, tells the Washington Post.

The biggest reservoir of rhyolitic magma found by the team is located in the northeastern area of Yellowstone. Below it, basaltic magma is migrating up from the lower crust, providing heat to the thick, explosive magma above.

Based on this mapping, the team predicts a shift in volcanic activity: If a rhyolitic eruption does occur at Yellowstone in the future, its center would most likely be in the northeast region of the park. This represents a change from the last 160,000 years, when most volcanic activity occurred elsewhere in the area, they write in the paper.

“The western part of the Yellowstone Caldera is waning,” Bennington tells USA Today’s Elizabeth Weise.

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Sarah Kuta is a writer and editor based in Longmont, Colorado. She covers history, science, travel, food and beverage, sustainability, economics and other topics.