Published: Sat, October 20, 2018
Sci-tech | By Patricia Wade

This Antarctic Ice Shelf Sounds Dark And Foreboding Like Doom Metal

This Antarctic Ice Shelf Sounds Dark And Foreboding Like Doom Metal

As noted by Earther, the frozen region's ambient sounds include the Rice Crispies-like crackle of melting ice releasing long-trapped air bubbles to the steady groans, screeches, and pops of massive floating ice sheets shifting and breaking apart as they buckle under the weight of fresh snow in the winter or melt during the summer. Now researchers from Antarctica's Ross Ice Shelf have found something new, which is interesting as well as creepy at the same time.

As it turns out, the sounds actually come from powerful winds blowing through snow dunes on the surface of the ice shelf itself. Changes in air temperature and wind speed also affected how the vibrations traveled through the snow and ice.

"Ice shelves are a critical element of the Antarctic glacier system", says Rick Aster, a geophysicist at Colorado State University and a coauthor of the new study.

"Either you change the velocity of the snow by heating or cooling it, or you change where you blow on the flute, by adding or destroying dunes", Chaput said.

This allowed them to monitor the "near‐surface conditions" of the giant ice shelf, which is roughly the size of Texas (or Spain, for Europeans).

Study co-author Rick Aster during a station installation trip on the Ross Ice Shelf
Study co-author Rick Aster during a station installation trip on the Ross Ice Shelf

But if we deployed seismic sensors on more ice shelfs, you could observe subtle environmental changes, in minutes.

The lowest frequency a human can hear is only 20 Hz, and even then this is only possible in extreme anechoic chambers, but we can "feel" sounds lower than that, for example during earthquakes.

Chaput told Global News that now, ice shelf monitoring is limited to satellite sweeps, which are few and far between. Listening for changes to the hum could indicate how the shelf is responding to changing weather conditions and whether it's in danger of cracking, the researchers report this week in Geophysical Research Letters.

"The response of the ice shelf tells us that we can track extremely sensitive details about it", Chaput said. Antartica is experiencing an accelerating loss of mass from its ice shelves, which act as plugs holding back the world's largest stores of ice from flowing uninhibited into the ocean.

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