| Title | 3-D Interpretation of Magnetotelluric Data at the Atadei Geothermal field, Lembata Island, Indonesia |
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| Authors | Toshihiro Uchida,Tae Jong Lee, Ashari, and Arif Munandar |
| Year | 2002 |
| Conference | PNOC-EDC Geothermal Conference |
| Keywords | |
| Abstract | We conducted an MT survey at the Atadei geothermal field, Lembata Island, Indonesia, and performed a three-dimensional (3-0) interpretation for the detailed investigation of geothermal reservoirs. The 3-0 inversion scheme used in this work is based on the linearized iterative least-squares method with smoothness regularization. The fotward modeling for a given arbitrary 3-0 earth is by the finite difference method. In addition to resistivities of the blocks representing a 3-0 earth, static shitts are also treated as unknown parameters in the inversion. Starting fmm a homogeneous half space, the iterative model refinement by the least-squares method is repeated until the misfit does not change as the iteration proceeds. An optimum smoothness and an optimum weight for the static-shiit minimization are searched based on the misfit minimization at each iteration. The inversion worked properly on the field data and reasonably small misfit was achieved. It suggests that the treatment of the static shitts in the inversion is essential. The obtained 3-0 resistivdy model indicated a low-resistivrty shallow layer around the surface manifestations. The deep high-resistivity basement was also delineated beneath the low-resistivity layer. These features preliminary suggested a reservoir Structure in the area. |