Active volcano holds clues to violent landslides

Huge, volcano-triggered landslides can alter the seabed when they tumble into the ocean and sweep across the sea floor. Now scientists are studying these effects by braving an active volcano.

A scientific team led by Peter Talling of the UK's National Oceanography Centre (NOC) is currently aboard the Royal Research Ship James Cook to map extremely large landslide deposits that cover a large area offshore from the Soufriere Hills volcano on Montserrat in the Lesser Antilles.

The volcano has been erupting episodically since 1995, with the last major eruption and volcanic dome collapse occurring in February 2010. Volcanic dome collapses occur when dome-shaped lava mounds on top of a volcano break apart due to a gas pressure build-up. Soufriere Hills' eruptions have produced some of the largest volcanic dome collapses ever recorded.

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Thousands of years ago, a large collapse of the Soufriere Hills' edifice sent landslides into the ocean. Some of these landslides involved nearly 1.2 cubic miles (5 cubic kilometers) of material that travelled underwater for miles. However, a complete survey of such a deposit has never been produced.

"We plan to produce the first detailed survey of this type of volcanic flank collapse deposit," Talling said. "For the first time, we will image flank-collapse deposits by collecting three-dimensional seismic reflection data, which will show how huge avalanches were emplaced."

The research....

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