Abstract

One of the main problems in resistivity surveys is the terrain effect because of which the true interpretation of the subsurface structure may be biased. There are two approaches to deal with this problem: i) terrain-correction that uses correction factors in a homogeneous earth or ii) inversion that incorporates topography. Some terrain models such as hills and slopes are used to evaluate the effect of the terrain on the 2D modelling and inversion where the finite elements method is used for the forward modelling. The least-squares inversion technique is used to estimate the resistivities within each block of the model structure. The forward modelling results indicate that the terrain topography significantly contaminates the subsurface response. The terrain-correction used to eliminate the topography effect helps to isolate the response of the real subsurface. The inversion incorporating topography also gives reliable results if correct host rock resistivity is used in the process.

Key words: Electrical resistivity, topography, modelling.