Scientists blow up ice in Antarctic

New Zealand scientists have detonated explosives to help reveal how Antarctica’s ice shelves might respond to a warming world.

A team led by the University of Otago’s Associate Professor David Prior has spent the past three weeks camping out at remote Terra Nova Bay for one of this season’s most intriguing research projects on the ice.

Prior said the main aim was to find what controlled a process called ice deformation — and how ice sheets might respond to temperature changes or shifting conditions at ice shelf edges.

In both Antarctica and Greenland, increases in the rate of flow of ice from the land to the sea caused global sea levels to rise.

While it was already clear that climate change influenced this process, there was less certainty about the rate of sea level change that would come in the next few years.

That made understanding how ice flow would respond to the changing climate critically important.

A big driver of ice flow was ice deformation — and this happened where the fast-moving Priestley Glacier met slow-moving ice at what’s called the shear margin.

Prior’s project was taking a deeper look at the effect by drilling holes in the glacier, placing explosives in them, and letting them off.

“We recorded the explosions and ice behaviour through geophones and the speed of the sound waves will tell us about the physical properties of ice,” he said.

The data they gathered was “almost pristine” — and aligned with how they predicted the glacier to react, save for a few surprises along the way. “One of the things we did was record the glacier continuously, not just when we let explosions off.

“What we found was there is a massive amount of activity in the ice in the morning for about four to five hours as the day warms up.

“We think this has to do with the surface of the ice warming but it is going to need more investigation.”

It was the first time this type of seismology research has been carried out on the shear zone of a glacier.

Antarctica New Zealand chief scientific adviser Dr Fiona Shanhun said the work wouldn’t have been possible without support from the Korean Polar Research Institute.

“The team stayed at Jang Bogo Station which is the Korean base in Terra Nova Bay, about 350km north of Scott Base,” she said.

This collaboration demonstrates the importance of working with other countries’ programmes to better understand ice dynamics in a warming world, she said.