Theoretical properties of the Fourier spectrum of the magnetic anomaly due to a two-dimensional body of finite depth extent

Abstract

An expression for the total field magnetic anomaly due to a two-dimensional prismatic body of finite depth extent is formulated and its Fourier transform is derived. Properties of the Fourier energy density and phase spectra are related to the body parameters. The null positions of the energy density spectrum are related to the width of the prism; the slope of the modified energy density spectrum is related to the depth and susceptibility of the prism. Properties of the phase spectrum are related to the dip and thickness of the prism. This analysis may also be extended to magnetic anomalies in vertical and horizontal components with a few modifications. Application of this method on a synthetic anomaly yielded reasonably accurate results.