Two-Dimensional Cross-Gradient Joint Inversion of Gravity and Magnetic Data by a Sequential Strategy

Abstract

Summary This study tries to model an already approved potash source by cross-gradient joint inversion of the available gravity and magnetic data via a sequential strategy. The target source has been located in NW Iran. Different geophysical methods generally have different inversion systems. Especially they may differ in model parametrization and inversion algorithm. Thus, combining these different systems and yet including the nonlinear cross-gradient constraint in a joint inversion framework might be a big challenge. By decoupling gravity inversion, magnetic inversion and the cross gradient minimization, the proposed algorithm tries to avoid these challenges. At first the efficiency of the algorithm and developed code is shown by joint inversion of noisy synthetic data. There is an improvement of the cross-gradient joint inversion results over the separate inversions both for synthetic and field data. The density and magnetization models obtained for field example are in high concordance with available geological information, the drilling results, and previous studies. Specifically, there is a significant improvement in magnetization model affected by more trustable density model via the cross-gradient constraint.