Sounds in the earth may predict avalanches

GENEVA, Switzerland (UPI) — Forecasting avalanches may be possible by listening for increases of icequakes and their distinctive sounds, Swiss researchers say.

Geologists listening in on the groan and creak of icequakes — cracking inside frozen soil or rock containing water or ice — have developed a model that can predict a collapse up to 15 days before it happens, reported Friday.

To find early warning signs of an avalanche, scientists in Switzerland placed seismic instruments on a glacier on the northeast face of the Weisshorn, a mountain in the Swiss Alps that towers over the village of Randa, 8,200 feet below. Avalanches on the Weisshorn have claimed 51 lives since the 17th century.

In 2003 researchers froze a special microphone called a geophone into the glacier to pick up seismic vibrations.

Two weeks before the glacier split in 2005, researchers detected changes in the sounds picked up by the microphone.

“As you approach rupture, you hear more sounds,” geologist Jerome Faillettaz says. “It’s just like if you break a pen or a cracker. You hear some small noise before it breaks.”

By combining observations of a glacier’s slow movement with the sounds of the icequakes, the researchers say they can detect a rupture 15 days in advance.

Copyright 2010 by United Press International

Sourced & published by Henry Sapiecha