INTERPRETATION OF INDUCTION ANOMALIES ABOVE NONUNIFORM SURFACE LAYERS

Abstract

Using convolution integrals to account for the inductive coupling between surface layer and substratum, we derive the conductance of a nonuniform surface layer above a layered substratum by direct inversion from the system’s anomalous inductive response to natural geomagnetic variations. The conductivity in the substratum and the uniform conductance of the surface layer at some distance from the nonuniformity (two‐dimensional) must be known. The convolution method is also applied to the reverse problem: finding the anomalous inductive response for a given two‐dimensional nonuniformity. Our calculations are based on Price’s thin‐layer approximation.