30 November, 2000

A Seismic Adventure

Communications cleared up this morning so we hosted a couple of flights today. First, an LC-130 flew in for refueling on its way back to McMurdo. Then the Twin Otter arrived to take science teams into the field.

Sridhar Anandakrishnan and Jerry Bowling from the University of Alabama along with Don Voigt of Penn State University are conducting a seismic study. They have a series of six seismometers placed around West Antarctica. These instruments record earthquakes in Antarctica as well as larger events in the Southern Hemisphere. This data provides information about the structure of the Earth's crust.

Today they were off to perform maintenance and download data from one of their seismic stations. I was really excited when they said I could tag along for the day.

A. This is our ride for the day. The Twin Otter is taking on fuel before we take off.

B. The plane can hold about twenty passengers. Four our flight there were four passengers and lots of gear including a snowmobile.

C. Our route took us from Siple Dome northeast across Ice Stream D to a site designated ISDE. The distance of 305 kilometers(190 mi) took about 80 minutes to cover.

D. The ice streams move ice from the West Antarctic Ice Sheet down to the Ross Ice Shelf. The ice moves as much as one to two meters a day. As it goes over uneven terrain, the ice cracks creating a series of crevasses. These snow-covered crevasses, visible from the plane, are probably several meters across and very deep.

E. After landing at ISDE we unloaded the gear. Before a plane can leave, communications must be established. Here, Don contacts McMurdo on the high-frequency radio.

F. Sridhar, Jerry, and Don test the seismometer that they pulled from its position two meters below the surface.

G. Each seismic station is powered by solar cells and wind generators. Information about the station's status can be relayed by way of an orbiting ARGOS satellite.