South Pole Seismograph Station QSPA

The geographic South Pole is a unique location for seismological observations of the earth because of its location on the spin axis of the Earth. Seismological observations at the South Pole began in 1957 during the International Geophysical Year (IGY). The seismographic instruments were periodically upgraded, but as they became increasingly sensitive through the years, noise from the nearby station activities became more and more troublesome. In order to achieve the lowest possible background seismic noise conditions at South Pole, it became necessary to install the seismometers at much greater distance from cultural noise sources and at greater depth than they had been previously. A study in 1997 indicated that high quality seismic observations should be obtainable by installing the seismometers at a distance of 5 to 30 km from South Pole Station and at a depth of 200 to 500 meters. Noise would be attenuated more for even greater distances and depths, but there are significant logistical limitations. The location finally chosen is 8 km from South Pole Station and 300 m below the surface.

To accommodate the new seismometers, ICDS was tasked to drill three holes 12 inches in diameter to a depth of 300 m. This was accomplished by coring with a 4" drill, then reaming the holes to 12" in two stages. The primary work took two seasons under the direction of lead drillers Louise Albershardt (first half of 2001-02) and Terry Gacke (remainder of the project), assisted (for part or all of the project) by drillers Bella Bergeron, Mark Albershardt, Matt Pender, Mat Kausch, Jay Johnson, and Denise Braun; it was completed early enough in January, 2003, for the US Geological Survey to install their seismometers (at a depth of about 275 m) before the end of the season. Kent Anderson of USGS served with the drilling crews during both seasons as USGS coordinator. A third, reserve hole was completed and instrumented in the 2003-04 field season.

The borehole seismic installation and vault installation at QSPA are part of the South Pole Remote Earth Science and Seismological Observatory (SPRESSO) within the Quiet Sector of the South Pole. The performance of the QSPA has been beyond expectations -- it is the seismically quietest station in the entire Global Seismographic Network at frequencies above 1 Hz. Real-time data from QSPA may be viewed at www.liss.org, and further information on the GSN may be found at http://www.iris.edu/about/GSN/