Interpretation of 1D Vector Controlled-Source Audio-Magnetotelluric (CSAMT) Data Using Full Solution Modeling
Keywords:1D Occam inversion, controlled-source audio-magnetotellurics, full solution 1D CSAMT forward modeling, scalar CSAMT, vector CSAMT interpretation.
AbstractIn conventional controlled-source audio-magnetotelluric (CSAMT) prospecting, scalar CSAMT measurement is usually performed because of its simplicity and low operational cost. Since the structure of earthâ€™s conductivity is complex, the scalar CSAMT method can lead to a less accurate interpretation. The complex conditions need more sophisticated measurements, such as vector or tensor CSAMT, to interpret the data. This paper presents 1D vector CSAMT interpretation. A full solution 1D CSAMT forward modeling has been developed and used to interpret both vector and scalar CSAMT data. Occamâ€™s smoothness constrained inversion was used to test the vector and scalar CSAMT interpretations. The results indicate the importance of vector CSAMT to interpret CSAMT data in complex geological system.
Goldstein, M.A., & Strangway, D.W., Audio-Frequency Magnetotellurics with A Grounded Electric Dipole Source, Geophysics, 40, pp. 669-683, 1975.
Unsworth, M.J., Travis, B.J., & Chave, A.D., Electromagnetic Induction by a Finite Electric Dipole Source Over a 2D Earth, Geophysics, 58, pp. 198-214, 1993.
Mitsuhata, Y., 2-D Electromagnetic Modeling by Finite-Element Method with a Dipole Source and Topography, Geophysics, 65, pp. 465-475, 2000.
Li, Y., & Key, K., 2D Marine Controlled-Source Electromagnetic Modeling: Part 1 " An Adaptive Finite-Element Algorithm, Geophysics, 72, pp. WA51-WA62, 2007.
Streich, R., 3D Finite Difference Frequency Modeling of Controlled Source Electromagnetic Data: Direct Solution and Optimization for High Accuracy, Geophysics 74, pp. 95-105, 2009.
Sasaki, Y., Yoshihiro, Y., & Matsuo, K., Resistivity Imaging of Controlled-Source Audiofrequency Magnetotelluric Data, Geophysics, 57, pp. 952-955, 1992.
Yamashita M., Hallof, P.G., & Pelton, W.H., CSAMT Case History with a Multichannel CSAMT System and Near Field Data Correction, 55th SEG Annual Convention, pp. 276-278, 1985.
Bartel, L.C., & Jacobson, R.D., Results of a Controlled Source Audiofrequency Magnetotelluric Survey at the Puhimau Thermal Area, Kilauea Volcano, Hawaii, Geophysics, 52, pp. 665-677, 1987.
Routh, S.P., & Oldenburg, D.W., Inversion of Controlled Source Audio Frequency Magnetotelluric Data for a Horizontally Layered Earth, Geophysics, 64, pp. 1689-1697, 1999.
Zonge, K.L., & Hughes, L.J., Controlled Source Audiofrequency Magnetotellurics, in: Nabighian, M.N. (ed.), Electromagnetic Electromagnetic Methods in Applied Geophysics: Volume 2, Application, Society of Exploration Geophysicist, Tulsa, Oklahoma, 1991.
Constable, S.C., Parker R.L, & deGroot, C., Occam's Inversion: A Practical Algorithm for Generating Smooth Models from EM Sounding Data, Geophysics, 52, pp. 289-300, 1987.
Kaufman, A.A., & Keller G.V., Frequency and Transient Sounding, Elsevier, Amsterdam, 1983.
Ward, S.H., & Hohmann, G.W., EM Theory for Geophysical Applications, in Nabighian, M.N. (ed.), Electromagnetic Methods in Applied Geophysics, Vol. 1: Theory, Society of Exploration Geophysicist, Tulsa, Oklahoma, 1988.
Singh, N.P., & Mogi, T., EMDPLER: A F77 Program for Modeling the EM Response of Dipolar Sources over the Non-Magnetic Layer Earth Model, Computer and Geosciences 36, pp. 430-440, 2010.
Cagniard, L., Basic Theory of the Magneto-Telluric Method of Geophysical Prospecting, Geophysics, 18, pp. 605-635, 1953.
Anderson W.L., Numerical Integration of Related Hankel Transform of Order 0 and 1 by Adaptive Digital Filtering, Geophysics 44, pp. 1287-1305, 1979.
Anderson, W.L., A Hybrid Fast Hankel Transforms Algorithm for EM Modeling, Geophysics, 54, pp. 263-266, 1989.
Srigutomo, W., Kagiyama, T., Kanda, W., & Utada, H., Study of Deep Sounding Time Domain EM (TDEM) Method using Horizontal Electric Dipole to infer Subsurface Resistivity Structure. Indonesian Journal of Physics, 16, pp. 115-125, 2005.
Aster, R.P., Borchers, B., & Thurber, C.H., Parameters Estimation and Inverse Problems, Elsevier Academic Press, Oxford, U.K., 2005.