Dilution and Distortion Effects in the Induced Polarization Response of a Two-Layer Earth

Using a two-layer Earth model the effective complex resistivity is computed for various frequencies and plotted in the complex Argand plane along with the first- and second-order dilution theoryapproximations. In the first case the frequency dependence of the complex resisitivity for the bottom region has a Cole-Cole form, but theupper layer is nonpolarizable. In this situation we demonstrate that theapparent resistivity does not always agree with dilution theory results,and the departure is most severe when the upper layer is relatively wellconducting. In the second case, both layers are polarizable, and we findthat the resulting dispersion is not a Cole-Cole form.