Studies and applications of 2-D CSAMT modeling and inversion with a dipole source and topography
起伏地形下CSAMT二维正反演研究与应用

In the exploration of ore with CSAMT in mountainous area, various filtering and phase integral method often cannot handle calibration for uneven terrain and local electrical static effect. To develop a new method to eliminate static effect is important for improving the CSAMT data processing and interpretation and application effect. Taking eliminating terrain effect as the main target, this paper adopts the 2D earth and 3D source terrain model and uses the weighted cosine integral method to carry out finite-element calculation in wave-number domain. To simulate complex terrain we selected cross-symmetrical triangular grid to realize forward calculation of 2D CSAMT data for the electrical equatorial dipole array, which is popular in China. On the basis of the 2D forward calculation, we developed a set of rolling terrain 2D CSAMT inversion technique based on the OCCAM method. Through theoretical calculation and real data processing, the terrain effects could be effectively corrected. In prospecting application, the comparison of results with available geological data shows that the terrain and static effects, which resulted in distortion of apparent resistivity, could be effectively corrected, the resulted distribution of resistivity clearly reflects the geoelectrical feature, with geological structure and anomalous bodies outlined.