Higher Levels of CO2 in Magma Results in Violent Volcanic Eruptions

Volcanologists at the University of Georgia (UGA) in collaboration with two Swiss universities have discovered a connection between carbon dioxide and the volume of gas caught in magma, which could help forecast the magnitude and intensity of a volcanic eruption.

They discovered that higher levels of CO₂ result in an increase in the total volume of gas in magma, which may lead to fierce and explosive eruptions.

The new results of the study could enable improved early warning systems for people who live close to volcanoes. However, Mattia Pistone, the lead author of the study, warned that more research is required to develop such a practical application.

Pistone, who is an assistant professor of geology at the Franklin College of Arts and Sciences at UGA, collaborated with Luca Caricchi from the University of Geneva and Peter Ulmer from the Swiss Federal Institute of Technology to find the role that gas geochemistry plays in the volume of gas that trapped in magma by mimicking what happens in magma chambers before volcanic eruptions.

This produced a true, original result. If you have more CO₂ in the magma, then that will increase the volume of gas stored in the magma. Adding more CO₂ in the magma implies bad news in terms of volcanic hazard.

Mattia Pistone, Assistant Professor of Geology, Franklin College of Arts and Sciences, University of Georgia

Together with his fellow investigators, Pistone developed a research question as soon as they noted 'strange' and unanticipated data from an earlier project.

The team made a comparison of CO₂-rich magma with water-rich magma and noted that magma rich in CO₂ resulted in the trapping of a higher volume of gas in magma before the occurrence of volcanic eruptions.

Gaseous CO₂ favors the presence of gas bubbles that tend to remain trapped in the magma. If you increase the CO₂ content—which increases the volume of gas in the magma—the volcano is not going to erupt gently. It’s going to erupt explosively.

Mattia Pistone, Assistant Professor of Geology, Franklin College of Arts and Sciences, University of Georgia

Pistone’s 'Magma Mia lab' will test pre-eruptive conditions of volcanoes. The amount of CO₂ trapped in magma relies on certain factors, such as the physical composition of the magma, the location of the volcano on Earth, and the architecture of the volcanic system.

The study results can now be used by volcanologists to take the impact of gas geochemistry into account while trying to find out the magnitude and intensity of a volcanic eruption in the future.

I hope there will be a new debate among volcanologists, where what we achieved experimentally can be further confirmed in the near future by studies in the field with new data. I hope there’s a ripple in volcanology to rephrase research questions and address new research lines, providing new insights on how to investigate active volcanic systems.

Mattia Pistone, Assistant Professor of Geology, Franklin College of Arts and Sciences, University of Georgia

“Laboratory simulations capture only a few aspects of the more complex natural volcanic scenarios and cannot be used directly in how we assess volcanic hazard and risk. I hope the impact of my research can be relevant in this,” added Pistone.

Journal Reference:

Pistone, M., et al. (2020) CO₂ favours the accumulation of excess fluids in felsic magmas. Terra Nova. doi.org/10.1111/ter.12496.