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Laterally Constrained Inversion of GREATEM data

지상 송신원 항공 전자탐사 자료의 횡적 제한 역산

  • Cho, In-Ky (Division of Geology and Geophysics, Kangwon National University) ;
  • Jang, Je-Hun (Division of Geology and Geophysics, Kangwon National University) ;
  • Yi, Myeong-Jong (Mineral Resources Division, Korea Institute of Geoscience and Mineral Resources) ;
  • Rim, Hyoung-Rae (Mineral Resources Division, Korea Institute of Geoscience and Mineral Resources)
  • 조인기 (강원대학교 지질.지구물리학부) ;
  • 장제훈 (강원대학교 지질.지구물리학부) ;
  • 이명종 (한국지질자원연구원 광물자원연구부) ;
  • 임형래 (한국지질자원연구원 광물자원연구부)
  • Received : 2016.11.29
  • Accepted : 2017.01.23
  • Published : 2017.02.28

Abstract

Recently, the grounded electrical-source airborne transient electromagnetic (GREATEM) system with high power source was introduced to achieve deeper investigation depth and to overcome high noise level. Although the GREATEM is a transient electromagnetic system using a long grounded wire as the transmitter, GREATEM data have been interpreted with 1D earth models because 2D or 3D modeling and inversion of vast airborne data are complicated and expensive to calculate. Generally, 1D inversion is subsequently applied to every survey point and combining 1D images together forms the stitched conductivity-depth image. However, the stitched models often result in abrupt variations in neighboring models. To overcome this problem, laterally constrained inversion (LCI) has been developed in inversion of ATEM data, which can yield layered sections with lateral smooth transitions. In this study, we analysed the GREATEM data through 1D numerical modeling for a curved grounded wire source. Furthermore, we developed a laterally constrained inversion scheme for continuous GREATEM data based on a layered earth model. All 1D data sets and models are inverted as one system, producing layered sections with lateral smooth transitions. Applying the developed LCI technique to the GREATEM data, it was confirmed that the laterally constrained inversion can provide laterally smooth model sections that reflect the layering of the survey area effectively.

Acknowledgement

Supported by : 강원대학교, 한국지질자원연구원

References

  1. Abd Allah, S., and Mogi, T., 2016, Three-dimensional resistivity modeling of GREATEM survey data from Ontake Volcano, northwest Japan, Earth, Planets and Space, 68, 68-76. https://doi.org/10.1186/s40623-016-0450-0
  2. Auken, E., and Christiansen, A. V., 2004, Layered and laterally constrained 2D inversion of resistivity data, Geophysics, 69, 752-761. https://doi.org/10.1190/1.1759461
  3. Auken, E., Christiansen, A. V., Jacobsen, B. H., Foged, N., and Sorensen, K. I., 2005, Piecewise 1D laterally constrained inversion of resistivity data, Geophysical Prospecting, 53, 97-506. https://doi.org/10.1111/j.1365-2478.2005.00486.x
  4. Cho, I. K., Kim, R. Y., and Yi, M. J., 2015, One-dimensional Modeling of airborne transient electromagnetic using a long grounded-wire source, Geophysics and Geophysical Exploration,18, 216-222. https://doi.org/10.7582/GGE.2015.18.4.216
  5. Cho, I. K., and Lim, J. T., 2003, One-dimensional inversion of electromagnetic frequency sounding data, Geophysics and Geophysical Exploration, 6, 180-186.
  6. Christensen, N. B., Reis, E., and Halkjaer, M., 2009, Fast, laterally smooth inversion of airborne time-domain electro-magneticdata, Near Surface Geophysics, 7, 599-612.
  7. Constable, S. C., Parker, R. L., and Constable, C. G., 1987, Occam's inversion: A practical algorithm for generating smooth models from EM sounding data, Geophysics, 52, 289-300. https://doi.org/10.1190/1.1442303
  8. Cox, L. H., Wilson, G. A., and Zhdanov, M. S., 2010, 3D inversion of airborne electromagnetic data using a moving footprint, Exploration Geophysics, 41, 250-259. https://doi.org/10.1071/EG10003
  9. Cox, L. H., Wilson, G. A., and Zhdanov, M. S., 2012, 3D inversion of airborne electromagnetic data, Geophysics, 77, WB59-WB69. https://doi.org/10.1190/geo2011-0370.1
  10. Ellis, R. G., 1995, Airborne electromagnetic 3D modelling and inversion, Exploration Geophysics, 26, 138-143. https://doi.org/10.1071/EG995138
  11. Ellis, R. G., 1998, Inversion of airborne electromagnetic data, Exploration Geophysics, 29, 121-127. https://doi.org/10.1071/EG998121
  12. Gunderson, B. M., Newman, G. A., and Hohmann, G. W., 1986, Three-dimensional transient electromagnetic responses for a grounded source, Geophysics, 51, 2117-2130. https://doi.org/10.1190/1.1442064
  13. Kaufman, A. A., 1994, Geophysical field theory and method, Part B, Electromagnetic filed I, Academic Press, INC., 1-169.
  14. Lee, T., and Lewis, R., 1981, The effect of host rock on transient electromagnetic fields, Exploration geophysics, 12, 5-12. https://doi.org/10.1071/EG981005
  15. Macnae, J., 2007, Developments in broadband airborne electro-magnetics in the past decade, in B. Milkereit, ed., Proceedings of Exploration 07: Fifth Decennial International Conference on Mineral Exploration, 387-398.
  16. Mogi, T., Kusunoki, K., Morikawa, T., and Jomori, N., 1998, Development of grounded electrical source airborne EM(GREATEM), Exploration Geophysics, 29, 61-64. https://doi.org/10.1071/EG998061
  17. Mogi, T., Kusunoki, K., Kaieda, H., Ito, H., Jomori, A., Jomori,N., and Yuuki, Y., 2009, Grounded electrical-source airborne transient electromagnetic (GREATEM) survey of Mount Bandai, north-eastern Japan, Exploration Geophysics, 40, 1-7. https://doi.org/10.1071/EG08115
  18. Monteiro Santos, F. A., 2004, lD laterally constrained inversion of EM34 profiling data, Journal of Applied Geophysics, 56, 123-134. https://doi.org/10.1016/j.jappgeo.2004.04.005
  19. Nabighian, M. N., 1979, Quasi-static transient response of a conducting half-space - An approximate representation, Geophysics, 44, 1700-1705. https://doi.org/10.1190/1.1440931
  20. Oristaglio, M. L., 1982, Diffusion of electromagnetic fields into the earth from a line source of current, Geophysics, 47, 1585-1592. https://doi.org/10.1190/1.1441309
  21. Raiche, A., 1998, Modelling the time-domain response of AEM systems, Exploration Geophysics, 29, 103-106. https://doi.org/10.1071/EG998103
  22. Siemon, B., Auken, E., and Christiansen, A. V., 2009, Laterally constrained inversion of helicopter borne frequency-domain electromagnetic data, Journal of Applied Geophysics, 67,259-268. https://doi.org/10.1016/j.jappgeo.2007.11.003
  23. Tartaras, E., and Beamish, D., 2006, Laterally constrained inversion of fixed-wing frequency-domain AEM data, Proceedings of Near Surface 2006, Helsinki, B019.
  24. Vallee, M. A., and Smith, R. S., 2009a, Application of Occam's inversion to airborne time-domain electromagnetics, The Leading Edge, 28, 284-287. https://doi.org/10.1190/1.3104071
  25. Vallee, M. A., and Smith, R. S., 2009b, Inversion of airborne time-domain electromagnetic data to a 1D structure using lateral constraints, Near Surface Geophysics, 7, 63-71.
  26. Ward, S. H., and Hohmann, G. W., 1987, Electromagnetic theory for geophysical applications, in Electromagnetic method in Applied Geophysics, SEG, 1-132.
  27. Wilson, G. A., Cox, L. H., and Zhdanov, M. S., 2010, Practical 3D inversion of entire airborne electromagnetic surveys, Preview, 146, 29-33.
  28. Wisen, R., and Christiansen, A. V., 2005, Laterally and mutually constrained inversion of surface wave seismic data and resistivity data, Journal of Environmental & Engineering Geophysics, 10, 251-262. https://doi.org/10.2113/JEEG10.3.251
  29. Wisen, R., Auken, E., and Dahlin, T., 2005, Combination of 1D laterally constrained inversion and 2D smooth inversion of resistivity data with a priori data from boreholes, Near Surface Geophysics, 3, 71-79.
  30. Yi, M. J., Kim, J. H., and Chung, S. H., 2003, Enhancing the resolving power of least-square inversion with active constraint balancing, Geophysics, 68, 931-941. https://doi.org/10.1190/1.1581045
  31. Zhdanov, M. S., and Tartaras, E., 2002, Three-dimensional inversion of multi-transmitter electromagnetic data based on the localized quasi-linear approximation, Geophysical Journal International, 148, 506-519. https://doi.org/10.1046/j.1365-246x.2002.01591.x