Yellowstone National Park isn’t going to erupt anytime soon, and a new study from the United States Geological Survey (USGS) has proven it’s less likely than ever.
Ninfa Bennington was the lead author of a study published in Nature that collected “magnetotelluric data” on the molten magma deep under the surface of Yellowstone. The team of volcanologists used that data to create a high-resolution map of magma bodies in the northeast corner of the park.
Many people and news outlets saw the research as a sign that Yellowstone is active and “on the move.” However, the factual conclusions from this new research should be reassuring rather than unnerving.
“This study reinforces the fact that we're not worried about a volcanic eruption from Yellowstone,” Mike Poland, scientist in charge of the Yellowstone Volcano Observatory, told Cowboy State Daily. “A volcanic eruption just doesn't appear to be something that's going to happen anytime soon.”
A Better Look Inside
Yellowstone’s magma chamber has been thoroughly studied and monitored using seismic tomography. That technique measures the speed of the seismic waves generated by the magma chamber to determine how much of it is melted.
Seismic tomography has been an incredibly useful method of monitoring volcanoes for decades. Poland said magnetotellurics is a similar but different technique that uses the latest technology to get a better picture of what’s melted under the earth's surface.
“Magnetotellurics looks at the electromagnetic characteristics of the subsurface of a volcano that's also sensitive to where magma may be present,” he said. “It’s allowing us to see the details of the magmatic system at a level that wasn’t possible before.”
Poland likened the new study's results to a photo taken with a high-resolution camera. Future research combining seismic tomography and magnetotelluric data could reveal a wealth of new information on what is and isn’t happening underneath Yellowstone.
“The first study of Yellowstone's magmatic system was done in 2015, and all it revealed was a couple of blobs,” he said. “New data collection methods, experiments, and computing power that looked at all the volume of data collected have started to reveal things in more and more detail. Jointly interpreting these data sets is an exciting new avenue.”
A Solid Conclusion
Whenever “Yellowstone” and “magma” appear in a study, the immediate conclusion is that volcanologists are anticipating or monitoring an impending eruption. Not only was that not the focus of the new USGS study, but the data collected came to nearly the opposite conclusion.
Poland said that while the new magnetotelluric data provided a better map of Yellowstone’s magma chambers, they reached the same conclusion as previous seismic tomography studies: the situation under Yellowstone isn’t very fluid, and that’s a good thing.
“One thing the authors of the study emphasized was that there were very low percentages of actual molten material in the magma chambers,” he said. “Areas of melt could be identified using the magnetotelluric method, and that showed that there isn’t a lot of magma present in a liquid form of the subsurface.”
While the “viscosity” of magma varies from volcano to volcano, the types and intensities of eruptions are determined by how much and how fluid their magma is. With Yellowstone’s magma chamber being mostly solid, the risk of an eruption is considerably low.
Poland wasn’t surprised by that conclusion, which reaffirms previous studies assessing the potential threat of a Yellowstone eruption. Still, multiple scientific studies that come to the same, not-so-dangerous conclusion are never a bad thing.
“This is a completely independent data set that shows the Yellowstone magmatic system is mostly solid,” he said. “There’s not a lot of molten magma in a liquid form that’s eruptible, and there are no eruptive vents in that part of the system.”
Yellowstone National Park's most famous attraction, Old Faithful Geyser, shows the thermal forces percolating underneath the region. (Andrew Rossi, Cowboy State Daily) 
Yellowstone National Park's most famous attraction, Old Faithful Geyser, shows the thermal forces percolating underneath the region. (Andrew Rossi, Cowboy State Daily) 
Yellowstone National Park's most famous attraction, Old Faithful Geyser, shows the thermal forces percolating underneath the region. (Andrew Rossi, Cowboy State Daily) 
Yellowstone National Park's most famous attraction, Old Faithful Geyser, shows the thermal forces percolating underneath the region. (Andrew Rossi, Cowboy State Daily) 
Yellowstone National Park's most famous attraction, Old Faithful Geyser, shows the thermal forces percolating underneath the region. (Andrew Rossi, Cowboy State Daily) 
A pair of tourists in winter watch Castle Geyser in the Upper Geyser Basin of Yellowstone National Park. (Andrew Rossi, Cowboy State Daily) 
Old Faithful Geyser in Yellowstone National Park percolates under as clear night sky. (Andrew Rossi, Cowboy State Daily) 
Old Faithful Geyser in Yellowstone National Park percolates under as clear night sky. (Andrew Rossi, Cowboy State Daily) 
Old Faithful Geyser in Yellowstone National Park percolates under as clear night sky. (Andrew Rossi, Cowboy State Daily)
Where The Real Danger Lies
While the study concluded that Yellowstone’s magma is much more solid than liquid, plenty of dangers lurk under the park's surface. Poland and the scientists who authored the new study cautioned that explosions and earthquakes are much more common and concerning than eruptions.
“Hazards like hydrothermal explosions and major earthquakes could occur in the Yellowstone region, and they are much more relevant on human time scales,” Poland said.
The July 2024 explosion of Black Diamond Pool was a potent reminder of the dangers lurking just under the surface of Yellowstone. It was determined to be a hydrothermal explosion caused by tremendous energy generated when water suddenly changed to steam.
Despite the force and size of the explosion, Yellowstone Volcano Observatory determined that the Black Diamond Pool incident wasn’t volcanic. Poland said the park’s hydrothermal hazards are indirectly related to the volcano’s magmatic behavior.
“Hydrothermal explosions are caused by near-surface changes,” he said. “The magmatic system is providing the heat that heats the water up, but there's a lot of silica precipitating on these hot water conduits. That can seal up a conduit, build pressure tens of feet beneath the surface, and eventually result in an explosion. That doesn't require any change in the magmatic system whatsoever.”
Hydrothermal explosions can range in size and intensity. Craters from these explosions range from a few feet to several miles in diameter.
Furthermore, a plethora of earthquakes occur in Yellowstone every year. While most of these are too small to be felt, there’s always the potential for a large earthquake to cause damage throughout the Greater Yellowstone region.
Compared to these hazards, which could occur anywhere at any time in Yellowstone, the threat of a volcanic eruption is pretty toothless. Poland’s not losing any sleep over it, and neither should anyone else.
Yellowstone Saves The World?
Yellowstone National Park's abundant geothermal and hydrothermal activity makes it one of the most studied volcanoes on the planet, making it an invaluable asset to volcanologists worldwide.
Poland said every study that reveals more about Wyoming’s massive volcano reveals more about volcanoes overall, particularly those that pose a much more serious risk of catastrophic eruptions.
“The more we understand Yellowstone, the more we can understand similar systems, and vice versa,” he said. “Yellowstone remains a wonderful example of similar volcanic systems around the world. When we understand more about Yellowstone through studies like this, we can apply that to other volcanoes worldwide, whether they’re in Italy, New Zealand\ or Japan.”
Fortunately, Yellowstone remains as dynamic as ever. Even if the massive volcano won’t blow its top anytime soon, it has plenty more to reveal about volcanoes, and those discoveries may help save lives in the future.
“It’s a dynamic place,” Poland said, “The volcanological community benefits from everything we learn in Yellowstone National Park.”
Andrew Rossi can be reached at arossi@cowboystatedaily.com.
