Seismic study allows scientists to see below glacier
A glimpse beneath the ice
The Totten Glacier is the largest in East Antarctica.
It stretches 30 kilometres across and up to 2 kilometres deep.
But little is known about what lies beneath this mass of ice, whether it’s bedrock or water.
Dr Ben Galton-Fenzi “By understanding how much ocean is under the glacier we can then understand how susceptible they are to climate change.”
For the first time researchers have found a network of lakes underneath the glacier using seismic testing.
They set off a series of small explosions two metres below the surface of the glacier, sending out sound waves.
Dr Ben Galton-Fenzi “That will echo off different layers in the ice and the bottom of the ice. Then we have geophones, that are basically microphones on the surface, that will listen to that sound and that will tell us how thick it is and the characteristics of the ice and the ocean below the ice.”
The research will help better predict future sea level rise.
Australian Antarctic Program researchers have undertaken seismic studies on the largest glacier in East Antarctica, revealing for the first time a network of lakes beneath the ice.
The team of international researchers spent the summer working on the Totten Glacier, near Casey research station, to find out if there is bedrock or water, as subglacial lakes or ocean, 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.”
The flow of water in and out of these lakes has the potential to exert a powerful control on the rate that the ice flows into the 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.
This project was supported by the Australian Research Council Antarctic Gateway Partnership and the Antarctic Climate and Ecosystems CRC.
This summer season more than 550 expeditioners travelled south with the Australian Antarctic Program working on more than 56 projects.
Australia’s icebreaker RSV Aurora Australis spent a total of 164 days at sea, while the Airbus A319 and RAAF C-17A aircraft made a 10 return flights to Wilkins Aerodrome.