Opportunities for an Interdisciplinary Seismic Observatory at the South Pole, Antarctica

Abstract:

The U.S. Geological Survey has operated the seismic station SPA (South Pole, Antarctica) out of Amundson-Scott Station since 1963 as an extension of International Geophysical Year (1957-1958) efforts. Seismograms from the station have been important for seismological observations for over six decades by providing (until recently) the only continuous seismic records from the interior of the Antarctic continent and because it is the only location on the Earth where long-period (> 200 s) normal-mode oscillations of the planet excited by large earthquakes can be recorded without influence from Earth’s rotation. Normal-mode and other far-southern hemisphere observations from the station are critical for constraining deep-Earth structure.

˚

The station has undergone many updates over the years including being converted to a digitally recording station as part of the Global Seismographic Network in 1991 and being re-located to 255 m deep boreholes 8 km away from the station in 2003 (and renamed to QSPA). QSPA has enabled a variety of seismological and glaciological studies, including identifying ice stream stick-slip events and studying megaiceberg collisions in the Ross Sea. However, the current sensors are largely a 1980s technology and, while able to make some long-period observations from earthquakes are unable to resolve ambient ground motions at periods longer than 40 s. Recently developed borehole sensors offer the potential to extend these background noise observations to beyond 200 s which would substantially improve the fidelity and scientific value of seismic observations (including earthquake signals) at South Pole. We will review seismic observations at and near South Pole Station and discuss future opportunities through interdisciplinary collaboration with the IceCube Neutrino Observatory to update the instrumentation. Potential avenues being explored include emplacing a modern, very broadband seismometer near the base (~2400 m depth) of the Antarctic ice cap, which could lead to unprecedented seismic observations at long-periods.