Fiber optic cables reveal ‘icequakes’ in endangered glaciers

Scientists in Switzerland have found a new way to study why glaciers are breaking apart, using ordinary fiber optic cable laid across the ice. The method, called distributed acoustic sensing, sends laser pulses through the cable and reads tiny disturbances in the light to detect vibrations. A grid of cable can act like thousands of seismometers at once, picking up "icequakes" — small fractures that shake the ice much like a tiny earthquake.

Researchers led by Thomas Hudson at ETH Zurich used this setup on an alpine glacier and recorded more than a thousand icequakes in just one week. The quakes come from a process called hydrofracturing: meltwater seeps into cracks, and because liquid water is denser than ice, it forces the cracks open wider and deeper. This weakens the glacier's structure, which matters especially where glaciers sit above towns or train lines. The same forces are also at work in much larger ice sheets in Greenland and Antarctica, where melting and cracking contribute to global sea level rise.

This is early-stage science, not a product or service homeowners can buy or use. But it points toward better tools for predicting glacier collapse and, potentially, earlier warnings before events like the recent flooding disaster in Nepal. The researchers say the technology is cheap and easy to deploy compared to older monitoring equipment, which could make wider, long-term glacier monitoring more realistic in the future.