Magnetotelluric response of a two-dimensional sloping contact by the finite element method

Summary The finite element method, with triangular elements, is used to study the effect of a two-dimensional sloping contact on the surface electromagnetic fields. It is found in the case ofH-polarization and small slopes that the electric field and the apparent resistivity near the contact, on the conductive side, are higher than their asymptotic values. In the case ofE-polarization the apparent resistivity and phase values on the conductive side fall off less rapidly to their asymptotic values with decreasing slope resulting in higher apparent resistivity and phase values on the conductive side, than those expected for a vertical contact. The peak in the amplitude and phase of the normalized vertical magnetic field shifts from the resistive side for a vertical contact to the conductive side for a sloping contact. Far from the sloping contact, on the conductive side, higher values are observed for the normalized vertical magnetic field than in the case of a vertical contact.