2D and 3D algorithms of introcontinuation

The introcontinuation of a potential field for the localization of sources in the field's anomalies is discussed. A mathematical model of the field is proposed on the basis of the Dirichlet problem with a condition on the day surface. New 2D and 3D algorithms are developed to determine the critical points for the field continued into the lower half-plane. These algorithms are based on a finite-difference approximation of Berezkin's complete normalized gradient and on the determination of its critical points. Two versions of the finite-difference introcontinuation reduce a priori information requiring for the algorithms. A model experiment for the areal version (3D) procedure is considered to illustrate the determination of objects by the observed gravity field.