COMPUTATION OF GRAVITY AND MAGNETIC-ANOMALIES DUE TO INHOMOGENEOUS DISTRIBUTION OF MAGNETIZATION AND DENSITY IN A LOCALIZED REGION

Analytical expressions in the form of a convolution of two functions are derived. These expressions show explicitly that the anomalies are completely determined by the divergence of magnetization and the first vertical derivative of density. It is thus analytically established that when a body with uniform magnetization or density is considered, the impulsive change in the physical property of the rock mass at the boundary of the body is responsible for generating an anomalous magnetic or gravity field. These properties are utilized to derive efficient algorithms for computing gravity and magnetic anomalies. An example is given to demonstrate the usefulness of the derived algorithm in computing the anomaly due to magnetization of an irregularly shaped topography.