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International Journal of Geophysics
Volume 2013 (2013), Article ID 931876, 9 pages
http://dx.doi.org/10.1155/2013/931876
Research Article

3D DC Resistivity Inversion with Topography Based on Regularized Conjugate Gradient Method

School of Geosciences and Info-Physics, Central South University, Changsha 410083, China

Received 25 March 2013; Revised 30 July 2013; Accepted 21 August 2013

Academic Editor: Salvatore Piro

Copyright © 2013 Jian-ke Qiang et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

During the past decades, we observed a strong interest in 3D DC resistivity inversion and imaging with complex topography. In this paper, we implemented 3D DC resistivity inversion based on regularized conjugate gradient method with FEM. The Fréchet derivative is assembled with the electric potential in order to speed up the inversion process based on the reciprocity theorem. In this study, we also analyzed the sensitivity of the electric potential on the earth’s surface to the conductivity in each cell underground and introduced an optimized weighting function to produce new sensitivity matrix. The synthetic model study shows that this optimized weighting function is helpful to improve the resolution of deep anomaly. By incorporating topography into inversion, the artificial anomaly which is actually caused by topography can be eliminated. As a result, this algorithm potentially can be applied to process the DC resistivity data collected in mountain area. Our synthetic model study also shows that the convergence and computation speed are very stable and fast.