Inversion of gravity data in the Big Bear Lake Area to recover depth to basement using Cauchy-type integrals

Abstract

Summary One of the important applications of the gravity method is evaluation of the depth to the basement, which is characterized by a significant density contrast with the sedimental layeres. We have introduced recently a new method of modeling and inversion of potential field data generated by a density contrast surface based on 3D Cauchy-type integral representation of the potential fields (Zhdanov and Cai, 2013). The technique of the Cauchytype integrals makes it possible to represent the gravity field and its gradients as surface integrals. In the previous work, it was assumed that the density contrast between sediment and basement was a constant value. However, in some practical situations, the density of sediments may change with the depth. As a result, the density contrast between sediment and basement is also a function of depth. In this paper, we develop a method for modeling the gravity response caused by sediment-basement interface with variable density in depth. We have also developed the inversion of gravity data to recover the depth to basement given the density profile with depth.