Seismic and radar investigations of Fourcade Glacier on King George Island, Antarctica

  • Ki Young Kim
  • Joohan Lee
  • Myung Ho Hong
  • Jong Kuk Hong
  • Young Keun Jin
  • Howong Shon

Abstract

To determine P- and S-wave velocities, elastic properties and subglacial topography of the polythermal Fourcade Glacier, surface seismic and radar surveys were conducted along a 470-m profile in November 2006. P- and S-wave velocity structures were determined by travel-time tomography and inversion of Rayleigh wave dispersion curves, respectively. The average P- and S-wave velocities of ice are 3466 and 1839 m s-1, respectively. Radar velocities were obtained by migration velocity analysis of 112 diffraction events. An estimate of 920 kg m-3 for the bulk density of wet ice corresponds to water contents of 5.1 and 3.2%, which were derived from the average P-wave and radar velocities, respectively. Using this density and the average P- and S-wave velocities, we estimate that the corresponding incompressibility and rigidity of the ice are 6.925 and 3.119 GPa, respectively. Synergistic interpretation of the radar profile and P- and S-wave velocities indicates the presence of a fracture zone above a subglacial high. Here, the P- and S-wave velocities are approximately 5 and 3% less than in the ice above a subglacial valley, respectively. The S-wave velocities indicate that warmer and less rigid ice underlies 10–15 m of colder ice near the surface of the glacier. Such layering is characteristic of polythermal glaciers. As a relatively simple non-invasive approach, integration of P-wave tomography, Rayleigh wave inversion and ground-towed radar is effective for various glaciological studies, including the elastic properties of englacial and subglacial materials, cold/warm ice interfaces, topography of a glacier bed and location of fracture zones.

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Published
2010-12-01
How to Cite
Young Kim, K., Lee, J., Ho Hong, M., Kuk Hong, J., Keun Jin, Y., & Shon, H. (2010). Seismic and radar investigations of Fourcade Glacier on King George Island, Antarctica. Polar Research, 29(3), 298-310. https://doi.org/10.3402/polar.v29i3.6082
Section
Research/review articles