Paradox Of Anisotropy In Time-Domain Induced Polarization: Proof And Simulation

Based on an analytical solution for the point current source in an anisotropic half-space, we calculate the apparent resistivity and the apparent chargeability of a transversely isotropic medium with vertical and horizontal axes symmetry, respectively. We then provide a simple proof of the paradox of anisotropy in resistivity sounding and time-domain induced polarization. Analogous to the mean resistivity, we provide the formulation for deriving the mean polarizability. We also present a three-dimensional finite element algorithm for deriving the direct current resistivity and effecting time-domain induced polarization modeling using an unstructured tetrahedral grid. We then provide the apparent resistivity and apparent chargeability curves of a tilted, transversely isotropic medium with different angles, respectively. The subsequent results suggest our conclusions on the paradox of anisotropy in resistivity and time-domain induced polarization.