Scientists discover hidden activities in Bolivia’s ‘zombie’ volcano

According to research published in the Proceedings of the National Academy of Sciences on April 28, 2025, the seemingly inactive volcanoes in southwestern Bolivia are stirring the ground. Although no eruption has occurred for more than 250,000 years, the Uturuncu volcano has quietly expanded at a rate of 1 cm per year, driven by fluid migration and gas accumulation below the crater.

Dormant, but not dead: in volcanic “zombies”

Cornell researchers initially used satellite radar interference to detect signs of UTURUNCU activity, which revealed a unique targeted deformation pattern around volcanoes. The discovery prompted further research on this particular geological phenomenon.

“When people look at the volcano, they’re like, ‘Oh, if it doesn’t erupt, we’re not interested in it.’ But actually the volcano that looks dead on the ground isn’t dead below. “There’s still the process going on.” ”

The 25-year research project ended up in a comprehensive study that incorporates multiple scientific methods to gaze under the surface of a volcano. The researchers deployed 48 seismometer stations around UTURUNCU between 2009 and 2012, recording more than 1,700 earthquakes. They supplement these data by measuring gravity fields, natural currents and detailed rock analysis.

Create a “cat scan” of an ancient volcano

This multidisciplinary approach allows scientists to create something similar to three-dimensional medical scans inside volcanoes. Their findings suggest a complex magma thermal system with clear pathways for fluid migration to the surface and gas accumulation areas beneath the crater.

The research team includes scientists from Cornell University, the University of Science and Technology of China (USTC), Oxford University and Eth Zurich of Zurich, and has Ying Liu from USTC as the lead author of this article.

What makes this discovery particularly valuable is that its meaning goes beyond volcanic monitoring:

• A new way to assess the risk of other dormant volcanoes in the world
• Insights into how minerals form may help resource exploration
• Better understand long-term volcanic processes that have taken place over thousands of years
• Used to monitor other ‘zombie’ volcanoes around the world

Mineral formation

In addition to pure geological interest, Pritchard also noted that studying UTURUNCU provides real-time insights into economically important processes. The fluid movement through the volcanic system may help explain valuable mineral deposits.

“The idea is that liquid is flowing through the molten rocks, and they pick up some minerals on the way, and take them somewhere and store them,” Pritchard explained. “Even if we aren’t really worried about volcanic eruptions in the next few years, we can see the process in real time. Obviously, underground activities may even be economically useful at some point.”

Not alone: ​​A global phenomenon

UTURUNCU’s “zombie” identity is not unique. Pritchard’s satellite monitoring has identified similar volcanoes around the world, although dormant states have been showing signs of activity for centuries or thousands of years. Bolivia alone has about twelve dormant volcanoes that require continuous monitoring.

“These are unique beasts,” he said. “But they are not entirely rare.”

Although UTURUNCU itself may not pose an outbreak threat immediately, the study has implications for surveillance of its neighbors. As Pritchard points out, “Uturuncu may not be outbreaking, but some of these neighbors may.”

The study was supported by a variety of organizations, including the National Science Foundation, the National Environmental Research Council of the United Kingdom, the National Key Research and Development Programme of China, the National Natural Science Foundation of China and the Royal Society. Technical support comes from the Earthscope Alliance, its main instrument center at the New Mexico Institute of Technology.