Mount Etna: New Study Reveals Triggers for Violent Eruptions

Mount Etna, Europe’s most active volcano, exhibits two distinct explosive behaviors driven by the competition between water and carbon dioxide within its magma. According to a study published in Geochemistry, Geophysics, Geosystems by researchers from Cornell University, the University of Columbia, and the University of Hawái, these gas-driven mechanisms determine whether an eruption is a rapid, deep-seated event or a slower, surface-level catastrophe.

How Gases Dictate Volcanic Explosivity

Volcanic behavior is not uniform, even when the magma chemistry appears similar. Cornell University researchers found that the interplay between water and carbon dioxide (CO₂) fundamentally alters the eruption style of Mount Etna. When CO₂ dominates, the volcano tends to trigger rapid, deep-seated explosions. Conversely, when water plays the primary role, the process slows down as magma stalls in shallower crustal levels, leading to different explosive outcomes.

The Role of Deep-Earth Magma Storage

The study highlights two contrasting historical events to explain these risks. The “Fall Stratified” event, which occurred approximately 4,000 years ago, originated from depths of 24 to 30 kilometers. Because the magma was rich in CO₂, it ascended at a rate of 17.5 meters per second, triggering an eruption in mere hours. According to lead author Maxim Gavrilenko of Cornell University, the density of CO₂ measured in microscopic bubbles allows scientists to calculate the exact pressure and depth where magma was stored prior to an eruption.

Predicting Future Volcanic Hazards

Understanding these gas-driven cycles is essential for improving early warning systems in populated regions near active volcanoes. Professor Esteban Gazel of Cornell University notes that Mount Etna serves as an exceptional natural laboratory because it is one of the few places where water and CO₂ compete so clearly for control. By applying Raman spectroscopy to examine inclusions within olivine crystals, researchers can now reconstruct the ascent history of magma. This methodology is currently being extended to study volcanoes in Chile and Hawái, providing a framework for more accurate physical models of volcanic risk.

Frequently Asked Questions

• Why does the same volcano produce different types of eruptions?
  According to the Cornell study, the variation depends on which gas—water or carbon dioxide—is dominant and at what depth the magma is stored before it erupts.
• How do scientists know what happens deep underground?
  Researchers use Raman spectroscopy to measure the density of CO₂ in microscopic bubbles trapped inside olivine crystals, which acts as a “fossilized” record of the magma’s pressure and depth.
• Can these findings be used for other volcanoes?
  Yes, the researchers stated that these techniques are already being applied to evaluate volcanic risks in places like Chile and Hawái.

Have questions about how volcanic activity impacts regional safety? Share your thoughts in the comments below or join the conversation on our social media channels.