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Underground Cables Are Taking the Planet’s Pulse

Underground Cables Are Taking the Planet’s Pulse

Geologists are using fiber optics to monitor earthquakes, volcanoes, and traffic noise.
By Carolyn Wilke

This article was originally published in Knowable Magazine.

Andreas Fichtner strips a cable of its protective sheath, exposing a glass core thinner than a hair—a fragile, four-kilometer-long fiber that’s about to be fused to another. It’s a fiddly task better suited to a lab, but Fichtner and his colleague Sara Klaasen are doing it atop a windy, frigid ice sheet.

After a day’s labor, they have spliced together three segments, creating a 12.5-kilometer-long cable. It will stay buried in the snow and snoop on the activity of Grímsvötn, a dangerous, glacier-covered Icelandic volcano.

Carolyn Wilke is a freelance science journalist.