Seismic study cracks ice mysteries

A team of international researchers has undertaken seismic studies of the largest glacier in East Antarctica, revealing for the first time the network of lakes that lie beneath the ice.

The team spent the Summer working on the Totten Glacier to discover if there is bedrock or water under the ice.

Australian Antarctic Division glaciologist, Dr Ben Galton-Fenzi, said the speed at which the glacier travels is determined by what it moves across.

“If there’s bedrock under the glacier, it’s sticky and will move more slowly, but if there’s water or soft sediments, the glacier will move faster,” Dr Galton-Fenzi said.

“This study has shown us for the first time that there are substantial amounts of water contained in subglacial lakes, not far from the ocean, that we know very little about.”

According to the research, the flow of water in and out of the Antarctic lakes has potential to exert a powerful influence on the rate that ice flows in and out of the world’s oceans.

“So this research is critical in helping us predict how the melting of Antarctic glaciers will change the world’s oceans into the future.”

The seismic study involved setting off a series of small explosions at about two metres below the surface of the glacier.

“These explosions sent out sound waves, which then echoed off different layers in the ice and bedrock.

“We placed geophones along the surface of the glacier to listen to the reflected sound, giving us a picture of what lies beneath the ice.”

The Totten Glacier catchment, which is 30 kilometres wide and up to two kilometres thick, has the potential to raise sea levels by 7 metres, but more research is needed to accurately predict the rate at which this could occur.

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