LIMITING VALUES OF GRAVITATIONAL AND MAGNETIC ANOMALIES DUE TO A SUBTERRANEAN STRUCTURE BOUNDED BY A SINGLE DIFFERENTIAL SURFACE

Abstract

Calculations are made of gravitational and magnetic anomalies supposed due to local variations in the form of a single differential surface separating an overlying rock from an underlying one, the effective thickness of the latter being infinite. Both layers are homogeneous in density or magnetic susceptibility and only those magnetic effects are considered which are due to induction in the earth’s magnetic field. The maximum possible values of these anomalies and of their first and second horizontal derivatives are calculated under these simplified conditions, and it is pointed out that the numerical readings of these quantities, provided by survey results, may lead to useful estimates of the extreme depth and proportions of the structure responsible.