IRCG inversion of buried electrode resistivity data from an electrically conducting layered medium

Abstract

Electric potential resulting from the injection of direct current into the ground can be used to explore the earth’s structure. We propose to use an iteratively regularized inversion algorithm for the interpretation of buried electrode resistivity data gathered from a horizontally stratified layered earth. Two types of ground structures are used to investigate the electrical conductivity profiles. An iterative regularization scheme using the nonlinear conjugate gradient technique is applied to estimate the model parameters of conductivity variation. A suitable value of the regularization parameter is determined by using the well known L–curve criterion. The final inverted models obtained are in excellent qualitative agreement with the true models when using synthetic data. A comparison of inversion results obtained from our scheme and the Levenberg–Marquardt method on test data sets clearly demonstrates an edge over the other stated scheme as far as the robustness is concerned.