Helicopter-borne and ground-towed radar surveys of the Fourcade Glacier on King George Island, Antarctica
K. Y. Kim 1 4 J. Lee 2 M. H. Hong 1 J. K. Hong 2 H. Shon 31 Department of Geophysics, Kangwon National University, Chunchon, 200-701, Korea.
2 Korea Polar Research Institute, Incheon P.O. Box 32, 406-840, Korea.
3 Department of Civil, Environmental and Railroad Engineering, Pai Chai University, Daejon 302-735, Korea.
4 Corresponding author. Email: kykim@kangwon.ac.kr
Exploration Geophysics 41(1) 51-60 https://doi.org/10.1071/EG09052
Submitted: 14 November 2008 Accepted: 6 November 2009 Published: 19 February 2010
Abstract
To determine subglacial topography and internal features of the Fourcade Glacier on King George Island in Antarctica, helicopter-borne and ground-towed ground-penetrating radar (GPR) data were recorded along four profiles in November 2006. Signature deconvolution, f-k migration velocity analysis, and finite-difference depth migration applied to the mixed-phase, single-channel, ground-towed data, were effective in increasing vertical resolution, obtaining the velocity function, and yielding clear depth images, respectively. For the helicopter-borne GPR, migration velocities were obtained as root-mean-squared velocities in a two-layer model of air and ice. The radar sections show rugged subglacial topography, englacial sliding surfaces, and localised scattering noise. The maximum depth to the basement is over 79 m in the subglacial valley adjacent to the south-eastern slope of the divide ridge between Fourcade and Moczydlowski Glaciers. In the ground-towed profile, we interpret a complicated conduit above possible basal water and other isolated cavities, which are a few metres wide. Near the terminus, the GPR profiles image sliding surfaces, fractures, and faults that will contribute to the tidewater calving mechanism forming icebergs in Potter Cove.
Key words: Fourcade Glaciers, helicopter-borne and ground-towed GPR, internal features, subglacial topography.
Acknowledgments
This work was supported through the Korea Science and Engineering Foundation (KOSEF) grant R01–2007–000–20 194–0 by the Ministry of Science and Technology (MOST) and through the Grant PE09020 by the Korea Polar Research Institute (KOPRI). We thank Drs. Jong Ik Lee and Young Keun Jin at the KOPRI who supported us in many aspects of the fieldwork. We are also grateful to Dr Moon Young Choe, the 19th commander of King Sejong station, and his over-winter crews who allowed us to use all facilities at the station, provided transportation for the fieldwork, and otherwise assisted our fieldwork. We also thank two Chilean helicopter pilots at Presidente Eduardo Frei Montalva station for their careful flight above the glacier. Finally we appreciate Dr Raymond M. René at René Geophysics and Professor Hoonyol Lee at Kangwon National University for their helpful discussions and suggestions during the progress of this work.
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