Effects of 3D Topography on Magnetotelluric Responses

MT 탐사의 3차원 지형효과

  • Nam, Myung-Jin (Department of Petroleum and Geosystems Engineering, The University of Texas at Austin, Groundwater and Geothermal Division, Korea Institute of Geoscience and Mineral Resources) ;
  • Kim, Hee-Joon (Department of Environmental Exploration Engineering, Pukyong National University) ;
  • Song, Yoon-Ho (Groundwater and Geothermal Division,, Korea Institute of Geoscience and Mineral Resources) ;
  • Lee, Tae-Jong (Groundwater and Geothermal Division,, Korea Institute of Geoscience and Mineral Resources) ;
  • Suh, Jung-Hee (Department of Civil, Urban and Geosystem Engineering, Seoul National University)
  • 남명진 (한국지질자원연구원 지하수지열연구부) ;
  • 김희준 (부경대학교 환경탐사공학과) ;
  • 송윤호 (한국지질자원연구원 지하수지열연구부) ;
  • 이태종 (한국지질자원연구원 지하수지열연구부) ;
  • 서정희 (서울대학교 지구환경시스템공학부)
  • Published : 2007.11.30

Abstract

For precise interpretation of magnetotelluric (MT) data distorted by irregular surface terrain, topography effects are investigated by computing apparent resistivities, phases, tippers and induction vectors for a three-dimensional (3D) hill-and-valley model. To compute MT responses for the 3D surface topography model, we use a 3D MT modeling algorithm based on an edge finite-element method which is free from vector parasites. Distortions on the apparent resistivity and phase are mainly caused by distorted currents that flow along surface topography. The distribution of tipper amplitudes over both hill and valley are the same, while the tipper points toward the center of hill and the base of the valley. The real part of induction vector also points in the same direction as that of tipper, while the imaginary part in the opposite direction.

References

  1. 김희준, 남명진, 송윤호, 서정희, 2004, MT 법의 3차원 모델링 개관, 물리탐사, 7, 148-154
  2. 남명진, 2006, MT 탐사의 3차원 지형효과 분석 연구, 공학박사 학위논문, 서울대학교
  3. 박계순, 이춘기, 이희순, 권병두, 조인기, 오석훈, 2005, 경상분지 의 심부 지전기 구조, 한국물리탐사학회대한지구물리학회 공 동학술대회 논문집, 한국지질자원연구원, 2005년 5월 26-27일, 대전, 203-208
  4. 손정술, 송윤호, 정승환, 서정희, 2002, 벡터 유한 요소를 이용한 고주파수 3차원 전자탐사 모델링, 물리탐사, 5, 280-290
  5. 송윤호, 조인기, 김정호, 전정수, 1992, 제주도에서의 MT 탐사, 전기전자탐사 연구, KR-92-1G-5, 한국지질자원연구소, 33- 69
  6. 송윤호, 조인기, 김정호, 정승환, 전정수, 1993, MT 탐사-EMAP 탐사, 전기전자탐사 연구, KR-93-1G-7, 한국지질자원연구소, 37-86
  7. 송윤호, 이창범, 박덕원, 김형찬, 이철우, 이성곤, 박인화, 이태종, 심병완, 조병욱, 염병우, 이승구, 기원서, 현혜자, 손정술, 황세 호, 오재호, 이윤수, 박찬, 정용복, 김통권, 이진수, 고동찬, 안 은영, 윤욱, 2005, 심부 지열 에너지 개발 사업, 한국지질자원 연구원 기본사업 연차보고서, OAA2003001-2005(3), 과학기 술부, 147 p
  8. 이춘기, 이희순, 권병두, 조인기, 오석훈, 송윤호, 이태종, 정현기, 2004, 의성분지의 MT 탐사, 2004 대한지구물리학회-한국물리 탐사학회 공동학술발표회 논문집, 266-271
  9. 이태종, 송윤호, Uchida, T., 2005a, 심부 지열자원 개발을 위한 MT 탐사 자료의 2차원 역산 해석, 물리탐사, 8, 145-155
  10. 이태종, 송윤호, Uchida, T., 2005b, 포항 지열개발 지역 MT 탐 사자료의 2차원 및 3차원 해석, 한국지구시스템공학회지, 42, 297-307
  11. 정승환, 진명식, 김성재, 조진동, 구성본, 최위찬, 김원영, 최종호, 전명순, 조인기, 박영수, 지광훈, 이진수, 지세정, 신청천, 이병 주, 황상기, 이희일, 김광은, 윤욱, 최범용, 전정수, 김유성, 김 기석, 최선희, 1992, 마산 창원부근의 대규모 지역난방을 위한 지열에너지 탐사 및 개발연구, 921K101-113API, 동력자원부, 167 p
  12. 조인기, 정승환, 전정수, 1991, MT 탐사 연구, 전기전자탐사 연 구, KR-91-1G-5, 한국지질자원연구원, 33-69
  13. 조인기, 송윤호, 정승환, 김정호, 전정수, 1993, 원거리 기준점 MT 탐사, 전기전자탐사 연구, KR-93-1G-7, 한국지질자원연 구원, 1-34
  14. Berdichevsky, M. N., and Dmitriev, V. I., 2002, Magnetotellurics in the context of the theory of ill-posed problems, Soc. Explor. Geophys
  15. Chouteau, M., and Bouchard, K., 1988, Two-dimensional terrain correction in magnetotelluric surveys, Geophysics, 53, 854-862 https://doi.org/10.1190/1.1442520
  16. Druskin, V., and Knizhnerman, L., 1994, A spectral approach to solving three-dimensional diffusion Maxwell's equation in the time and frequency domains, Radio Science, 29, 937-953 https://doi.org/10.1029/94RS00747
  17. Goldstein, N. E., 1988, Subregional and detailed exploration for geothermal-hydrothermal resources, Geotherm. Sci. and Tech., 1, 303-431
  18. Honkura, Y., Niblett, B. R., and Kurtz, R. D., 1976, Changes in magnetic and telluric fields in a seismically active region of eastern Canada : Preliminary results of earthquake prediction studies, Tectonophysics, 34, 219-230 https://doi.org/10.1016/0040-1951(76)90097-4
  19. Key, K. W., Constable, S. C., and Weiss, C. J., 2004, Mapping 3D salt using 2D marine magnetotelluric method: Case study from Gemini Prospect, Gulf of Mexico, 74th Ann. Internat. Mtg, Soc. Expl. Geophys., Expanded Abstract, 596-599
  20. Lynch, D. R., and Paulsen, K. D., 1991, Origin of Vector Parasites in Numerical Maxwell Solutions, IEEE Trans. Microwave Theory Tech., 39, 383-394 https://doi.org/10.1109/22.75279
  21. Mackie, R. L., Smith, J. T., and Madden, T. R., 1994, Threedimensional electromagnetic modeling using finite difference equations: The magnetotelluric example, Radio Science, 29, 923-935 https://doi.org/10.1029/94RS00326
  22. Nam, M. J., Kim, H. J., Song, Y., Lee, T. J., Son, J.-S., and Suh, J. H., 2007a. Three-dimensional magnetotelluric modeling including surface topography, Geophysical Prospecting, 55, 277-287 https://doi.org/10.1111/j.1365-2478.2007.00614.x
  23. Nam, M. J., Kim, H. J., Song, Y., Lee, T. J., and Suh, J. H., 2007b. Three-dimensional topography corrections of magnetotelluric data, submitted to Geophysical Journal International
  24. Nedelec, J. C., 1980, Mixed finite elements in R3, Numr. Math., 35, 315-341 https://doi.org/10.1007/BF01396415
  25. Orange, A. A., 1989, Magnetotelluric exploration for hydrocarbons, Proc. IEEE, 77, 287-317
  26. Reddy, I. K., Rankin, D., and Phillips, R. J., 1977, Three-dimenstional modeling in magnetotelluric and magnetic variational sounding, Geophys. J. Roy. Astr. Soc., 51, 313-325
  27. Sasaki, Y., 1999, Three-dimensional frequency-domain electromagnetic modeling using the finite-difference method, Butsuri-Tansa, 52, 421-431. (in Japanese with English abstract)
  28. Smith, J. T., 1996, Conservative modeling of 3-D electromagnetic fields, Part II: Biconjugate gradient solution and an accelerator, Geophysics, 61, 1319-1324 https://doi.org/10.1190/1.1444055
  29. Solon, K. D., Jones, A. G., Nelson, K. D., Unsworth, M. J., Kidd, W. F., Wei, W., Tan, H., Jin, S., Deng, M., Booker, J. R., Li, S., and Bedrosian, P., 2005, Structure of the crust in the vicinity of the Banggong-Nujiang suture in central Tibet from INDEPTH magnetotelluric data, J. Geophys. Res., 110, B10102 https://doi.org/10.1029/2003JB002405
  30. Sugeng, F., Raiche, A., and Xiong, Z., 1999, An edge-element approach to model the 3D EM response of complex structures with high contrasts, Proc. 3-D EM II, 25-28
  31. Ting, S. C., and Hohmann, G. W., 1981, Integral equation modeling of three-dimensional magnetotelluric response, Geophysics, 46, 182-197 https://doi.org/10.1190/1.1441188
  32. Vozoff, K., 1991, The magnetotelluric method, in Nabighian M. N., Ed., Electromagnetic methods in applied geophysics, Soc. Explor. Geophys., Vol. II, 641-711
  33. Wang, T., and Hohmann, G. W., 1993, A finite difference, timedomain solution for three-dimensional electromagnetic modeling, Geophysics, 58, 797-809 https://doi.org/10.1190/1.1443465
  34. Wannamaker, P. E., Booker, J. R., Filloux, J. H., Jones, A. G., Jiracek, G. R, Chave, A. D., Tarits, P., Waff, H. S., Egbert, G. G., Young, C. T., Stodt, J. A., Martinez, M., Law, L. K., Yukutake, T., Segawa, J. S., White, A., and Green, A. W. Jr., 1989, Magnetotelluric observations across the Juan de Fuca subduction system in the EMSLAB project, J. Geophys. Res., 94, 14111-14125 https://doi.org/10.1029/JB094iB10p14111
  35. Wannamaker, P. E., Stodt, J. A., and Rijo, L., 1986, Two-dimensional topographic responses in magnetotelluric modeled using finite elements, Geophysics, 51, 2131-2144 https://doi.org/10.1190/1.1442065
  36. Yee, K. S., 1966, Numerical solution of initial boundary value problems involving Maxwell's equation in isotropic media, IEEE Trans. Anten. Prop., AP-14, 302-307
  37. Zhdanov, M. S., Wan, L., Constable, S., and Key, K., 2004, New development in 3D marine MT modeling and inversion for off-shore petroleum exploration, 74th Ann. Internat. Mtg, Soc. Expl. Geophys., Expanded Abstract, 588-591
  38. Zonge, K. L., and Hughes, L. J., 1991, Controlled source audiofrequency magnetotellurics, in Nabighian M. N., Ed., Electromagnetic methods in applied geophysics, Soc. Explor. Geophys., Vol. II, 713-809