Effective wave tilt and surface impedance over a laterally inhomogeneous two‐layer Earth

Using a perturbation method, we consider the effect of a simple two‐dimensional model on the electromagnetic fields at the surface of the Earth for a postulated downcoming plane wave. We examine the calculated change in the surface impedance and wave tilt due to lateral inhomogeneities. It is found that the magnetic wave tilt ( H z / H x ) is most seriously affected by such anomalies. This may have important consequences on electromagnetic probing of nonuniform portions of the Earth's crust.