Three-Dimensional Gravity Inversion in the Presence of the Sediment-Basement Interface: A Case Study in Utah, USA

Abstract

We introduce a novel approach to three-dimensional gravity inversion in the presence of the sediment-basement interface with a strong density contrast. This approach makes it possible to incorporate the known information about the basement depth in the inversion. It also allows the user to determine the depth-to-basement in the initial inversion phase. One can then use this interface to constrain the final inversion phase. First, the inversion generates the depth-to-basement model based on the 3D Cauchy-type integral representation of the gravity field. Then, in the second phase, full 3D voxel-type inversion applies the depth-to-basement model determined in the first phase as an a priori constraint. We use this approach to the 3D inversion of the Bouguer gravity anomaly data observed in Utah, USA. The results of inversion generated a 3D density model of the top layers of the earth’s crust, including unconsolidated sediments and the top of the crystalline basement.