How Glaciers Could Warn Us of Impending Volcanic Eruptions

We might be able to tell when a volcano is about to erupt with the help of another natural wonder: glaciers.
Glaciers that are within 3 miles of a volcano appear to move nearly 50 percent faster than the average glacier, according to a new paper in the journal Communications Earth & Environment.
This may help us use nature as an early warning system for eruptions of the 250 or so volcanoes, including Mt. Rainier in Washington, Mt. Redoubt and Mt Veniaminof. in Alaska, and Eyjafjallajokull in Iceland, all of which are closely neighbored by glaciers.
In the paper, the researchers describe how they analyzed the speed of travel from 214,086 glaciers—making up over 85 percent of the world’s glaciers.
They discovered that glaciers within 3 miles of a volcano flowed 46 percent faster than the average of those located elsewhere, even after controlling for climate, ice thickness and surface slope. Additionally, they found that the closer they are to active volcanoes, the faster they flow.
“This finding strongly suggests that volcanic heating impacts glacier velocity at a global scale, and supports the idea that glacier velocity monitoring could be a valuable indirect tool to help volcano monitoring and eruption prediction, particularly where volcanic heating (and therefore subglacial melt) intensifies months or years prior to eruptions,” the researchers wrote in the paper.
Glaciers around the world “flow” like slow-moving rivers, due to the force of gravity acting on the massive amount of ice they contain. This flow is a slow and continuous movement driven by several factors, including ice deformation, glacier creep, and melting at the base, reducing friction and allowing the glacier to slide over the bedrock.
This study indicates that nearby volcanoes may also contribute toward the melting and subsequent movement of glaciers, meaning that they could be used to predict eruptions.
“Recent studies have shown that the size, shape and elevation of glaciers can respond to volcanic activity, but the relationship between volcanism and glacier flow remained unknown. Our results suggest that satellite observations of glacier velocity could be a valuable new technique for monitoring volcanic activity and predicting eruptions,” study co-author Joseph Mallalieu, a glaciologist at the University of Birmingham in the U.K., said in a statement.
There are around 250 active volcanoes that currently have glaciers within a 3-mile radius, many of which have large towns and cities nearby. According to the paper, about 7 million people live within 18 miles of a glacierized, active volcano.
“Our research has notable implications for the mitigation of volcanic hazards. Ice-covered volcanoes are among the most dangerous globally because glacial meltwater released during eruptions can trigger outburst floods and debris flows capable of rapidly submerging nearby settlements,” Mallalieu said.
If we could use glacial movement to predict eruptions, we could potentially know months in advance if a volcano is about to explode, possibly saving many lives.
“If glacier velocity can be used as a precursor months before an eruption, it will help focus additional monitoring efforts on volcanoes likely to erupt, which in turn will alert decision makers,” co-author Matteo Spagnolo, a professor of geosciences at the University of Aberdeen in Scotland, said in the statement.
“It could provide much needed forewarning to local authorities to plan the possible evacuation of a nearby city, or impose a no-fly zone, without relying on last-minute decisions. It will also help prepare the local population for what might come well in advance.”
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Mallalieu, J., Barr, I. D., Spagnolo, M., Mullan, D. J., Symeonakis, E., Edwards, B. R., & Martin, M. D. (2024). Proximity to active volcanoes enhances glacier velocity. Nature. https://www.nature.com/articles/s43247-024-01826-5#Sec3