The curious case of the ‘singing’ Antarctic ice shelf


They left the sensors there for three years, and then analyzed the slow seismic hum generated by winds lashing snow against the surface of the ice sheet. The high frequency trapped seismic waves that ripple through the ice shelf were recorded by the researchers.

Chaput considers seismic monitoring to be a good way to keep an eye on Antarctica's ice shelves, which are considered to be among the most remote locales in the world.

But when the researchers actually analyzed the data, they came to a striking conclusion: the outermost layer of the ice shelf was nearly constantly vibrating.

While normally inaudible to the human ear, the researchers have made these ultra-low frequencies detectable to our limited hearing range.

Scientists who set out to watch the ice shift in Antarctica have ended up listening to it instead.

When they looked at the data, they realized the top layer of the shelf (called the firn) was nearly constantly vibrating, thanks to the winds travelling atop the snow dunes.

Ice shelves are covered in a thin blanket of snow, typically several meters deep, that insulates the ice below from warming and melting like a fur coat.

The vibrations themselves are believed to have been created by strong winds blowing across the dunes atop the Ross ice shelf, which vibrates the ice.

One of the researchers, Julien Chaput of Colorado State University, said: "It's kind of like you're blowing a flute, constantly, on the ice shelf", with each note change indicating a major structural change.

But beyond producing insane sounds, the research is providing invaluable insight into the changing weather conditions on our southernmost continent.

The difference in frequencies, or what Chaput describes as singing, happens as the surface of the snow dunes changes.

Chaput told Global News that now, ice shelf monitoring is limited to satellite sweeps, which are few and far between.

"Basically, what we have on our hands is a tool to monitor the environment, really", he added. "And that's essentially the two forcing effects we can observe".

The Ross Ice Shelf in Antarctica it is emitting tones reminiscent of a didgeridoo, or the drone of a horror film soundtrack.

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.