On automated interpretation of magnetic profile for a dipping contact model via total gradient and tilt angle transformation

Abstract

An automated method interpreting buried dipping contact model using total gradient and tilt angle transformation of the total magnetic intensity profile data. The workflow of processing total magnetic intensity data and the design detail of the algorithm for robust estimation of total gradient and tilt-angle of noise-contaminated total magnetic intensity data are provided. The robust estimation of horizontal and vertical gradients are obtained by using Savitzky–Golay derivative filter to estimate horizontal gradient and then using Hilbert transform with a spectral domain approach on the estimated horizontal gradient to estimate the vertical gradient. The model parameters viz. location of contact edge on a horizontal surface, depth of burial, dip and magnetic susceptibility contrast of the contact is estimated using a set of closed form formulas. Numerical experiments conducted on the noise contaminated synthetic total magnetic intensity profile data, demonstrate robustness in estimating model parameters. The method, applied to the magnetic profile across Paducah Gravity Lineament (PGL) at New Madrid Seismic Zone, USA, agrees significantly with previously interpreted results.