The Ross Ice Shelf in Antarctica has a haunting voice. Winds scouring its chilly snow dunes create waves of surface vibrations; these produce near-nonstop seismic tones that resemble a mournful song, scientists recently discovered.  

While the ice shelf's "music" is played at a frequency that isn't audible to human ears, the researchers were able to eavesdrop using seismic sensors, they wrote in a new study.

When they listened to recordings gathered over two years on the ice shelf, they found that the ice was almost constantly "singing" at a frequency of 5 hertz — five cycles per second — its doleful hum generated by the blowing of regional and local winds. They also learned that features of its song changed in response to events that affected the surface snow and ice, such as storms that shifted snow dunes' positions, or excessive melting. [Photos: Diving Beneath Antarctica's Ross Ice Shelf]

Scientists detected the vibration unexpectedly; they had installed 34 seismic sensors, on the Ross Ice Shelf from 2014 to 2017, to monitor other aspects of ice shelf behavior. But when they reviewed the readings, they noticed that the topmost snow layer was vibrating practically all the time from the active winds that whipped over its uneven surface, causing a seismic hum.

On the Ross Ice Shelf, the largest ice shelf in Antarctica, scientists are eavesdropping on the ice as it "sings."
On the Ross Ice Shelf, the largest ice shelf in Antarctica, scientists are eavesdropping on the ice as it "sings."
Credit: Michael Van Woert, National Oceanic and Atmospheric Association (NOAA) NESDIS, ORA

"It’s kind of like you're blowing a flute, constantly, on the ice shelf," lead study author Julien Chaput, a geophysicist and mathematician at Colorado State University in Fort Collins, said in a statement.

The pitch of the hum also changed subtly under certain conditions; after powerful storms altered the shape of the snow dunes, and when a warming event in January 2016 led to surface melt, they reported in the study.

Researchers lay the conduit that connects the seismometer to the solar power system (background) and recording components at a Ross Ice Shelf seismic station.
Researchers lay the conduit that connects the seismometer to the solar power system (background) and recording components at a Ross Ice Shelf seismic station.
Credit: Rick Aster

Monitoring the "song" of the ice shelf could allow scientists to track shifts in surface ice remotely, and practically in real time. This could help them piece together a more complete picture of ice shelf stability, and it could raise an early red flag if the shelf becomes vulnerable to collapse, the study authors concluded.

"Basically, what we have on our hands is a tool to monitor the environment, really — and its impact on the ice shelf," Chaput said in the statement.

The findings were published online Oct. 16 in the journal Geophysical Research Letters.

Originally publishedon Live Science.