Inside a huge walk-in freezer in suburban Denver, a college student in a thick parka shoots a jolt of electricity through a yard-long column of ice extracted from Antarctica.
Just outside the freezer, in a much warmer room, a computer wired to the ice registers a sudden spike in a jagged red line crawling across the screen.
“Hey, we got a volcano,” says T.J. Fudge, a University of Washington researcher. The electric current has detected a thin layer of volcanic residue in the ice, deposited by an eruption about 8,000 years ago.