Supervolcanoes are the most powerful volcanoes on Earth. A single supereruption can eject more than 1,000 cubic kilometers of material — enough to bury a major modern city under tens of meters of debris. Because of their potential to disrupt the environment, climate and human society, scientists have long sought to understand what drives their immense power.

Now, a team of scientists from China and the United States has provided the first comprehensive explanation of how the magma system beneath the Yellowstone caldera forms and persists over time. The study, conducted by researchers from the Institute of Geology and Geophysics of the Chinese Academy of Sciences and the University of Illinois, was published in the journal Science on Friday.

Researchers say it could improve future predictions of volcanic activity and help reduce disaster risks.

The Yellowstone caldera, located in Yellowstone National Park in western North America, is one of the world's best-known supervolcanoes. It has produced two massive eruptions over the past 2.1 million years, ejecting about 2,500 and 1,000 cubic kilometers of material, respectively. Its rich geological and geophysical data make it a natural laboratory for scientists.

For decades, scientists believed supervolcanoes were fueled by large pools of liquid magma stored within Earth's crust. In this model, the molten rock accumulates underground, building up pressure until it fractures surrounding rock and triggers an eruption. The heat source was thought to come from a vertical plume of hot rock rising from thousands of kilometers deep within Earth.

However, research over the past decade has challenged this view. Studies show that instead of a fully liquid pool, magma often exists as a "mush" — a mixture of molten rock and solid crystals — that can persist for long periods. In addition, geophysical data reveal that Yellowstone's magma system is tilted, rather than vertical, extending southwest as depth increases.

To better understand this structure, the research team developed a three-dimensional model of the region beneath western North America. The model integrates geological, geophysical and geochemical data to simulate both past and present Yellowstone activity.

The results suggest that magma originates much deeper than previously thought — near the base of the North American lithosphere, the rigid outer layer of Earth that extends about 100 kilometers underground.

At that depth, hot, partially molten rock flows slowly eastward through a narrow channel beneath Yellowstone. As this buoyant material gets entrained and stretched by the mantle flowing underneath the thicker part of the lithosphere, pressure drops sharply, causing the hot rock to melt and generate magma.

At the same time, the North American continent is moving westward, effectively pushing against this deeper flow. The interaction acts like opposing forces pulling apart the base of the continental lithosphere, creating a diagonal pathway through which magma can rise. This process explains the tilted shape observed in seismic studies.

"Our study provides the first comprehensive explanation of how magmatic systems beneath supervolcanoes form and evolve," said Liu Lijun, the study's corresponding author and a researcher at the institute.

Cao Zebin, the study's first author and a postdoctoral researcher, said the mechanism could apply to other major volcanic systems worldwide, including the Toba volcano in Southeast Asia and the Altiplano-Puna volcanic complex in South America.

Liu said the model may eventually be used to forecast volcanic activity in a way similar to weather prediction, helping authorities better anticipate eruptions and reduce associated risks. (China Daily)