Geophysics and Geophysical Exploration ISSN:1229-1064(Print) 2384-051X(Online) 지구물리와 물리탐사

This paper presents a practical inversion method for recovering a three-dimensional (3D) resistivity model andstatic shifts simultaneously. Although this method is based on a Gauss-Newton approach that requires a sensitivity matrix,the computer time can be greatly reduced by implementing a simple and effective procedure for updating the sensitivitymatrix using the Broyden's algorithm. In this research, we examine the approximate inversion procedure and the weightingfactor β for static shifts through inversion experiments using synthetic MT data. In methods using the full sensitivitymatrix constructed only once in the iteration process, a procedure using the full sensitivity in the earlier stage is usefulto produce the smallest rms data misfit. The choice of β is not critical below some threshold value. Synthetic examplesdemonstrate that the method proposed in this paper is effective in reconstructing a 3D resistivity structure from staticshiftedMT data.