SEGJ Technical Conference

Three-dimensional joint inversion of gravity and magnetic anomalies

Abstract We present a 3D joint inversion method to estimate two physical parameters, i.e., gravity and magnetization, of subsurface materials using field intensity measurements. In the method, we assume a linear relationship between the density and magnetization to relate the two parameters in a mathematical form. In the approach, the subsurface structure is discretized to a set of rectangular prisms. For estimating the density and magnetization of each prism, we minimize the quadratic norm of the residuals between the observed and the forward-modeled. Two regularization terms are used in our joint inversion. We also minimize the roughness and the similarity of the two physical parameters. The regularization parameters controlling the degree of roughness and similarity are determined in the L-curve criterion scheme. We apply our method to a numerical model which represents submarine massive sulphides (SMS). The joint inversion results, which have the advantages of both gravity and magnetic inversion, show better accuracy and resolution than the individual ones.