Scientists capture eerie seismic howl of Antarctic ice shelf

Rodiano Bonacci
Ottobre 20, 2018

"If the ice shelves come apart, then the restraining force is reduced, and the ice can flow faster from the interior of Antarctica into the ocean and increase the rate of contribution to sea level rises".

Mr Chaput and his team were using seismic sensors to learn more about the structure and movements of the Ross Ice Shelf, Antarctica's largest floating slab of ice, when they picked up the noises.

"We discovered that the shelf almost continuously sings at frequencies of five or more cycles per second, excited by local and regional winds blowing across its snow dune‐like topography", in a press release.

Studying these vibrations could give scientists a sense of how the Ice Shelf is responding to changing climate conditions, according to glaciologist Douglas MacAyeal from the University of Chicago, who was not connected with the study.

Study co-author Rick Aster during a station installation trip on the Ross Ice Shelf, holding a broadband seismometer. "Basically, what we have on our hands is a tool to monitor the environment, really".

Scientists heard the "song" of ice in Antarctica. Because of the constant wind, the snow like sand dunes in the desert. The team measured the vibrations (aka seismic waves) that moved through the shelf for a little over two years, and were able to detect in what ways the frequency shifted based on nasty storm events or heavy winds, seasonal changes or unusual shakeups in average temperatures, and so forth. "And its impact on the Antarctic ice sheet", the researcher added.

The normal human hearing range is 20Hz to 20,000Hz (though this upper limit drops off as we age) and the ice shelf "continuously "sings" at frequencies of five or more cycles per second (or 5Hz)". And ice shelves themselves are particularly important, since their melting accelerates the streaming of ice into the ocean from abutting ice sheets.

Changes to the ice shelf's "seismic hum" could also indicate whether cracks in the ice are forming that might indicate whether the ice shelf is susceptible to breaking up.

He believes the disturbances occurring on the surface are being trapped in the form of seismic waves which travel through the ice shelf.

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