A fast topographic correction method for electromagnetic data

Topography generally affects the electromagnetic data and will mislead the results of shallow layer's resistivity. In this paper, by analyzing the basic law of topography effect and classic ratio correction principle, it is feasible to replace the resistivity of uniform half space from numerical simulation by standard measured resistivity. We proposed a new fast method to correct the topographic effect in electromagnetic data. We obtain the surface resistivity without topography by using a small DC configuration, and then take it as standard resistivity to construct a new correction formula. Both synthetic and field data of CSAMT and TEM were processed using this method. Results show that the new method is a fast, effective and practical tool for topographic correction of electromagnetic data.