Scientists Discover a New Trigger for Volcanic Eruptions

Scientists may have discovered a new potential trigger for volcanic eruptions. They've found that a pressure drop associated with a structure known as a sill may actually trigger a volcanic eruption.

"Understanding the triggers for volcanic eruptions is vital for forecasting efforts, hazard assessment and risk mitigation," said Janine Kavanagh, one of the researchers, in a news release. "With more than 600 million people worldwide living near a volcano at risk of eruptive activity, it is more important than ever that our understanding of these complex systems and their triggering mechanisms is improved."

In order to study the mechanisms that trigger eruptions, the researchers used a tank filled with gelatin into which they injected colored water to mimic ascending magma. The scientists then used a high-speed camera and a synchronized laser to see what was going on inside the tank.

"It was at this point that we discovered a significant and previously unknown drop in pressure when the ascending vertical dyke stalled to form a horizontal sill," said Sandy Cruden, one of the researchers. "Sills often form in nature as part of a developing volcanic plumbing system, and a pressure drop can drive the release of dissolved gasses, potentially causing the magma to explode and erupt. It's similar to removing a cap from a bottle of shaken fizzy drink-the pressure drop causes bubbles to form and the associated increase in volume results in a fountain of foam erupting from the bottle."

The findings are important for volcanic monitoring systems around the world rely on the interpretation of signals of Earth's surface and subsurface measured by satellites, ground deformation devices and seismometers. These new findings may help researchers monitor this previously unknown potential eruption triggering mechanism.

The findings are published in the journal Earth and Planetary Science Letters.

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