Large-scale 3D inversion of Bathurst Mining Camp gravity gradiometry data

Abstract

Airborne gravity or gravity gradiometry surveys typically contain hundreds to thousands of line kilometers of data with measurement locations every few meters. The goal of 3D inversion of airborne gravity and/or gravity gradiometry (AGG) data is to recover the density distribution in a 3D earth model at an appropriate level of resolution and detail for subsequent use in geological interpretation. This is a challenging problem for a number of reasons. First, as mentioned, airborne surveys are characterized by very large data volumes. Second, the 3D modeling of large-scale surveys is a computationally challenging problem. In this paper, we discuss how these difficulties can be overcome by using a number of innovations, more specifically, the moving sensitivity domain approach, focusing regularization, and massively parallel computer implementation. We illustrate our method with an example of 3D inversion of AGG data collected by Bell Geospace over the Bathurst Mining Camp in New Brunswick, Canada.