지구물리와물리탐사 (Geophysics and Geophysical Exploration)

  • 제13권1호
  • /
  • Pages.51-60
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  • 2010
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  • 1229-1064(pISSN)
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  • 2384-051X(eISSN)
한국지구물리·물리탐사학회 (Korean Society of Earth and Exploration Geophysicists)
권호 표지

남극 킹조지섬 포케이드 빙하의 헬리콥터 및 지상 레이다 탐사

Helicopter-borne and ground-towed radar surveys of the Fourcade Glacier on King George Island, Antarctica

  • 김기영 (강원대학교 지구물리학과) ;
  • 이주한 (한국해양연구원 극지연구소) ;
  • 홍명호 (강원대학교 지구물리학과) ;
  • 홍종국 (한국해양연구원 극지연구소) ;
  • 손호웅 (배재대학교 건설환경철도공학과)
  • Kim, K.Y. (Department of Geophysics, Kangwon National University) ;
  • Lee, J. (Korea Polar Research Institute) ;
  • Hong, M.H. (Department of Geophysics, Kangwon National University) ;
  • Hong, J.K. (Korea Polar Research Institute) ;
  • Shon, H. (Department of Civil, Environmental and Railroad Engineering, Pai Chai University)
  • 투고 : 2008.11.14
  • 심사 : 2009.11.06
  • 발행 : 2010.02.18
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초록

남극 킹조지섬 포케이드 빙하의 저면 지형과 내부 모습을 규명하기 위해서 2006년 11월에 4개 조사측선을 따라 헬리콥터 및 지상 레이다(GPR) 탐사를 실시하였다. 혼합위상인 단채널 지상 GPR 자료에 적용한 신호 역대합, f-k 구조보정 속도분석, 유한차분 깊이구조보정 등의 처리과정을 통하여 수직 분해능 향상, 속도함수 추출, 선명한 깊이영상 작성 등을 효과적으로 수행하였다. 헬리콥터 GPR 자료의 경우, 구조보정속도는 공기와 얼음의 2층모델을 가정한 평균제곱근속도로 구하였다. GPR 단연은 울퉁불퉁한 빙저면, 빙하 내부의 미끄러짐면, 운집된 산란잡음 등의 특징적 모습을 보여준다. 기반암까지의 최대 깊이는 포케이드 빙하와 목지들로우스키 빙하 사이의 경계능선 남동사면에 인접한 빙하 골짜기에서 79 m가 넘는다. 빙하 기저수 위에 복잡한 형태의 굴과 수 m의 폭을 갖는 독립된 빈 공간들의 존재를 지상 GPR 자료로부터 해석하였다. 빙하 중단 부근의 GPR 영상은 포토소만의 빙산 형성기작과 관련된 미끄러짐면, 단열, 단층 등의 구조를 보여준다.

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 79m 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.

키워드

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