Detecting 'quakes in Antarctica

The science building at McMurdo Station where Don Voigt works stands on stilts so that snow can blow underneath it. The labs inside shake and rattle in the wind, making it difficult for Voigt, a Penn State geologist, to calibrate the intricate seismic equipment that he will use in the field.

Down the hall, heavy freezer doors lead outside where the temperature on a summer day usually reaches five degrees Fahrenheit. A warm day of 32 degrees inspires researchers to dance across the snow in t-shirts and shorts.

Voigt spends most of his time outside during a typical two-month research tour of Antarctica. This year, he will travel along the Transantarctic mountains—Santa-like in his bright red snowsuit and ice-encrusted beard—setting up sensitive instruments called seismometers that can detect the Earth's rumblings as far away as Tokyo and San Francisco.

Two years ago, Voigt began working with assistant professor of geosciences Andy Nyblade on a project called ANUBIS—Antarctic network of unattended broadband integrated seismometers. Voigt and a team of researchers set up six seismic stations on the ice. "The intent was to look at the way arriving earthquakes move through the mantle and crust," says Voigt.

Earthquakes send out waves that geologists call p and s waves. P waves, or primary waves, travel the fastest. S waves, or secondary waves, move behind the p waves. Researchers can tell how fast the waves are traveling by measuring the time it takes a wave to move from one seismic station to another. The speed of earthquake waves can reveal information about the material in the crust and upper mantle under the ice.

This year's project is called TAMSEIS—Transantarctic mountains seismic experiment. Forty-two seismic stations will collect the same sort of data, with a different intent: to understand how the Transantarctic mountains are being formed.

Setting up a seismic station can take several hours. Helicopters, small twin otter planes, and sometimes snowmobiles take the researchers from McMurdo to remote spots on the ice. "The first thing you do when you get out of the plane is stretch an antenna across the ice and make radio contact with McMurdo," says Voigt. "The plane can't leave until the research crew has communicated with McMurdo." Even then, he admits, it's a bit unnerving to watch your lifeline fly away. But, Voigt adds, "there's a certain amount of satisfaction in being so focused on a job.

"On a clear day, the visibility is unlimited. You can see the horizon seven miles away," says Voigt. "But when the wind starts blowing, it picks up loose snow and drops the visibility to nothing. There's no definition. Everything is white. Sometimes you can't even see your boot tops."

Antarctica, says Voigt, is an indescribable place. "As bleak as it seems, it's beautiful. Kind of like being at sea," he says. "When the winds cease, it's so quiet; you can hear your heartbeat."

Don Voigt, M.S., is a research assistant in the College of Earth and Mineral Sciences; dev2@psu.edu. Andy Nyblade, Ph.D., is assistant professor of geosciences in the Department of Geosciences; andy@geosc.psu.edu. Funding for ANUBIS and TAMSEIS comes from the National Science Foundation.