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Tent-bound
in Antarctica: Don Voigt warms up with
soup.
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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, 31 Hosler Bldg., University
Park, PA 16802; 814-865-3732; dev2@psu.edu. Andy Nyblade,
Ph.D., is assistant professor of geosciences in the
Department of Geosciences, 446 Deike Bldg.; 863-8341;
andy@geosc.psu.edu.
Funding for ANUBIS and TAMSEIS comes from the National
Science Foundation.
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