What is a Zombie Volcano?

The Earth is full of surprises, while some of them are shocking, others are scary as well, and among the most mysterious of natural phenomena are the ones that go beyond the expected results. Dead lakes come back to life, ancient rivers change course, and forests destroyed by wildfires sprout green within days.

These geological “resurrections” highlight how ever-changing and unpredictable the Earth's interior processes can be. Just because a volcano has been quiet for hundreds or even thousands of years doesn’t mean it’s truly dead.

Some volcanoes can appear completely dormant, giving local communities a sense of safety, but suddenly come back to life with a sudden shake of the inner layers of the Earth's core, ash plumes, or even eruptions. Such rare examples often pose a challenge to scientists in defining an “active” volcano.

Such phenomena remind us that Earth is very much alive and, in some cases, nature doesn’t close the book as neatly as we might hope. It may lie dormant, pause for years, then return with greater intensity.
What is this eerie volcano?
A " zombie volcano " is a term used to describe a volcano that has erupted, then gone extinct, and then unexpectedly becomes active again. The phrase tells about the surprising nature of such volcanic activity , just when a volcano is believed to be dead, it “rises from the grave.”

Although not a living, breathing thing like you and me, volcanoes experience their own “life cycles.” Filled with veins of magma and toxic gas rather than blood and plasma, these rumbling geologic formations first experience a calamitous active phase, a more sleepy dormant phase, until eventually going extinct.

A volcano that has not erupted in 250,000 years is showing signs of an imminent eruption.🥴

Uturuncu, a 'zombie' volcano in the Andes Mountains of Bolivia, has experienced increased seismic activity/gas emissions & the unrest is visible in a distinctive 'sombrero' pattern of… pic.twitter.com/D2RtQ3GhiK

— Mr Pål Christiansen (@TheNorskaPaul) May 11, 2025

Although technically not dead, dormant volcanoes usually show little activity unless they’re on the inevitable road to eruption. In a way, these volcanoes exist in a limited space between active and extinct. However, some volcanoes go as an exception in this easy category, and chief among them is the long-dormant Uturuncu volcano in Bolivia. Meaning “jaguar” in the indigenous language Quechua, Uturuncu hasn’t erupted for 2,50,000 years.

However, that hasn’t stopped this volcano from showcasing extensive gas and earthquake activity, causing some labeling it as a “zombie volcano.” Now, a new study from scientists at the University of Science and Technology of China (USTC), Oxford University, and Cornell University have unraveled the mystery of Uturuncu’s undead activity. The results of the study were published this week in the journal Proceedings of the National Academy of Sciences (PNAS).

Uturuncu, a “zombie” volcano in Bolivia, remains restless despite 250,000 years of dormancy. Recent findings reveal activity stems from underground fluid movement, not imminent eruptions, informing crisis evaluations at more than 1,400 potential volcanoes globally. pic.twitter.com/jMN6rDYQDK

— Nyra Kraal (@NyraKraal) April 28, 2025

Zombie volcanoes raise important questions about how volcanic dormancy is defined. A volcano is generally considered “active” if it has erupted in the last 10,000 years, “dormant” if it hasn't erupted recently but could again, and “extinct” if it’s not expected to erupt again. However, this classification is far from perfect.

Geologists are now using advanced technologies such as satellite radar, GPS, and ground-based sensors to detect subtle ground movements and gas emissions that can indicate volcanic activity long before any visible signs appear. As Power explained, “The unrest is a reminder that even long-dormant volcanoes can reawaken.”