Is Bolivia’s ‘Zombie Volcano’ Ready to Erupt? Scientists Investigate Signs of Increased Activity

Can a volcano come back to life? Uturuncu, a towering mountain in the Central Andes of Bolivia, is often called a “zombie volcano.” It hasn’t erupted in over 250,000 years but shows signs that hint at activity. Think gas clouds and small earthquakes—similar to what we see in active volcanoes.

Scientists have been closely monitoring Uturuncu. For over two decades, satellite images have revealed unusual movements near its summit, creating a sombrero-like shape. Researchers wanted to investigate if these changes meant the volcano might awaken from its long slumber.

By combining satellite data, seismic activity, and computer models, the team built a clearer view of what lies beneath the surface. Their findings, published in the journal Proceedings of the National Academy of Sciences, shed light on what’s causing Uturuncu’s unrest.

Typically, volcanoes erupt when molten rock, or magma, pushes toward the surface. If the magma is thick, it can trap gases, resulting in explosive eruptions. However, research reveals that under Uturuncu, magma, gases, and hot fluids are in a complex hydrothermal system, not rushing to the surface.

Located about 6 to 12 miles underground lies the Altiplano-Puna Magma Body—the largest known active magma reservoir on Earth. Previous studies suggested a link between this magma body and the mountain above, but how they interacted was not fully understood.

From 2009 to 2012, scientists tracked over 1,700 seismic events to create detailed images of the area beneath Uturuncu. They noticed electrical changes, shifts in gravity, and chemical changes in the rocks, painting a picture of a dynamic system at work.

The researchers found that as the magma heated underground water, it caused gases and liquids to move upward, collecting in chambers below the volcano’s crater. This activity triggered tremors, released steam, and changed the rock surface, leading to a rise of about 0.4 inches per year.

Despite these signs of life, experts believe Uturuncu won’t erupt anytime soon. Dr. Mike Kendall, a co-author of the study and a professor at Oxford, noted the absence of increasing seismic activity, which would normally signal magma on the move. Instead, it seems the volcano is merely releasing gas and calming down.

Dr. Benjamin Andrews, a geologist at the Smithsonian Institution, emphasized that using various methods provided clearer insights into Uturuncu’s underground structure. Alone, each technique could yield unclear results. Together, they illustrated the volcano’s hydrothermal system without suggesting an imminent eruption.

According to Andrews, understanding the interplay of magma, rock, and fluid is crucial. Not all volcanoes that show activity are ready to erupt. This research can help in exploring geothermal energy and essential minerals like copper and nickel found deeper within the Earth.

The Global Volcanism Program has identified about 50 zombie volcanoes globally, all showing signs of activity through geothermal features like hot springs. Some may be in a slow decline, while others could ramp up activity again someday. But as Dr. Matthew Pritchard from Cornell University notes, distinguishing between them remains a challenge.

Studying these volcanoes can reveal potential geothermal energy sources and uncover important minerals. Researchers are now equipped to analyze volcanoes of any kind, not just the “zombies.”

Understanding how these underground systems work helps assess risks and prepare for potential hazards. This knowledge is vital for assessing volcanic risks in regions around the world.

So, while Uturuncu might be a “zombie,” its inner workings offer valuable lessons for scientists everywhere. Exploring these hidden depths not only deepens our understanding of geology but also opens doors to sustainable energy and resource recovery.

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