Gravity inversion of 2.5D faulted beds using depth-dependent density

Abstract

A gravity inversion using Marquardt algorithm to simultaneously estimate four parameters of a 2.5D faulted bed in addition to regional gravity background is presented. The density contrast along the structure varied continuously with depth based on a parabolic function. Analysis of gravity anomalies over a synthetic fault structure using the present inversion unravelled the fact that the estimated parameters of a fault structure were independent of its strike length, as long as the profile bisected the fault plane. In case the profile failed to bisect the strike length, then the offset of the profile from the origin of the fault plane must be considered for reliable interpretation. A simulated parabolic density function of the Chintalpudi subbasin in India, was used to interpret the gravity anomalies of the Aswaraopet master fault. The estimated structure yielded a geologically plausible model that is consistent with borehole information.