An aerial shot of the Ross Ice Shelf in Antarctica. Scientists found that one of the largest ice shelves in the world was producing a low-level humid drumming on the snowy surface. The sound is almost continuous and changes pitch based on the situation on the surface. ( American Geophysical Union (AGU) | YouTube )
Antarctica is singing. Scientists found that one of the world's largest slabs of ice is producing an almost continuous series of tones.
The phenomenon was observed by accident at the Ross Ice Shelf. Scientists who were monitoring the vibrations of the largest ice shelves in the continent were "stunned" to discover the low-humored by the wind blowing over its snow dunes.
Geophysical Research Letters of the American Geophysical Union A study that discusses the seismic noise created by the Ross Ice Shelf.
The Singing Ice Shelf
Unfortunately, the gentle song of the ice shelves is too low for the human ear to hear -> 5 Hz frequency. To "listen" to the seismic tones of the Ross Ice Shelf, scientists buried sensitive sensors beneath the ice surface. A sped-up recording of what is released by the American Geophysical Union on its social media pages (watch below).
"It's kind of like you're blowing a flute, constantly, on the ice shelf," described geophysicist Julien Chaput, the lead author of the study.
The low ice of the Ross Ice Shelf is produced when the wind blows across the snow dunes, causing the surface to vibrate and produce a seismic tone. Scientists were at the site to study the low-frequency vibrations caused by earthquakes and ocean waves. However, upon closer look, they are vibrating the surface of the ice sheet.
They therefore found that the "hum of the ice shelf" has been changed according to weather conditions. The ice vibrates at different frequencies during a snow storm. The air temperature thus affects almost the seismic waves on the surface. The scientists compare the process to a musician changing the pitch of a note on a flute by altering the speed of air flow or picking which hole the air exits.
"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 explained.
Diagnosing The Ross Ice Shelf
The researchers hope that the changes to the ice shelf's seismic hum could reveal new details about the ice shelf, specifically if it is in danger of breaking apart.
The Ross Ice Shelf is the biggest slab of ice in Antarctica. It measures about 487,000 square-kilometers or about the size of Texas and France. It also plays an important role in stabilizing the ice sheet in the continent and acts as a "cork" that prevent glaciers from melting into the ocean.
Because of global warming, ice sheets in Antarctica are growing thinner. Some have been retired or even collapsed due to rising ocean and warming temperature.