Uturuncu, Bolivia — Geologists are examining the intriguing case of Uturuncu, a dormant volcano in the Central Andes, to determine if it may still harbor volcanic potential after centuries of inactivity. Known as a “zombie volcano,” Uturuncu last erupted over 250,000 years ago but exhibits signs of unrest, such as earthquake activity and gas emissions, prompting researchers to investigate whether it might soon awaken.
Recent studies utilized satellite radar imagery collected over the past two decades, revealing remarkable geological changes in the area surrounding Uturuncu’s summit. A significant section, measuring approximately 93 miles wide, has experienced notable uplift and depression, resembling a sombrero. This deformation raises concerns and curiosity about the volcano’s subsurface activity.
To gain insights into the volcano’s behavior, scientists combined satellite data with seismic activity analysis and advanced computer modeling. Their findings were published in a recent journal article, detailing the geological dynamics occurring beneath the surface.
Typically, volcanoes erupt when magma accumulates in hidden chambers beneath them, eventually forcing its way through fissures to the surface. However, the study found that beneath Uturuncu, a large magma reservoir known as the Altiplano-Puna Magma Body, about 6 to 12 miles deep, interacts with gases and mineral-rich fluids in a hydrothermal system. This interaction is responsible for the distinctive geological activity observed.
Between 2009 and 2012, researchers analyzed over 1,700 seismic events to develop detailed images of the volcano’s crust. They noted electrical and gravitational anomalies and shifts in rock chemistry. These observations suggested that gas and fluid movement beneath Uturuncu triggers localized quakes and surface deformations, with the volcano rising about 0.4 inches annually.
Despite its signs of unrest, study co-author Dr. Mike Kendall, a geosciences professor at the University of Oxford, believes Uturuncu is unlikely to erupt anytime soon. He noted that a significant increase in seismic activity or changes in seismic patterns often indicate imminent volcanic action, neither of which is currently observable. “It appears that the volcano is primarily releasing gas and steam rather than preparing for an eruption,” Kendall said.
Geologist Dr. Benjamin Andrews, director of the Global Volcanism Program at the Smithsonian Institution, emphasized the importance of using multiple research methods to gain clarity on Uturuncu’s subsurface interactions. He stated that separately examining seismic data and rock chemistry could yield inconclusive results. Together, these methods illuminate how magma, fluids, and geological structures interact beneath the surface.
Globally, researchers are monitoring approximately 50 zombie volcanoes, aged over 12,000 years but less than 2.6 million years, that show geothermal activity. Dr. Matthew Pritchard, a geophysicist at Cornell University, pointed out that while some of these volcanoes might have future eruptive potential, others may simply be in a prolonged state of decline.
Uturuncu and its counterparts offer valuable insights into volcano dynamics that could enhance our understanding of geothermal energy sources and mineral deposits vital for modern technologies. Kendall highlighted that analyzing volcanic structures not only aids in assessing eruption risks but also has implications for resource exploration.
The knowledge gained from studying these geological giants can help shape future research endeavors and risk management strategies, especially as scientists endeavor to distinguish between volcanoes likely to awake and those that may remain dormant for millennia.