Multiple joint inversion of geophysical data with sub-region crossgradient constraints

Crossgradient joint inversions, achieving structure coupling of multiple geophysical models, improve the reliability of inversion results, reduce the uncertainty of inversions, and reduce conflicts between results of different methods, in the case of unknown petrophysical relationships. When coverage of different observations is inconsistent, the crossgradient joint inversion usually need extract data corresponding to the overlapped region, and also expands the scope of some models. This paper proposed and implemented a multiple joint inversion of geophysical data with sub-region crossgradient constraints and followed by a synthetic model example. We have applied this method to comprehensive geological and geophysical interpretation of MT, gravity and magnetic field data sets for deep geological survey of Benxi-Ji'an. The results show that this algorithm not only can well restore similar structure model in the overlapped region, but the model parameters are varied smoothly on the boundary between overlapped and non-overlapped regions. The resistivity, density and susceptibility models, obtained from the joint inversion of Benxi-Ji'an survey line No. 10, are very similar in their structures, well reflect the deep geological structure of this area, and provide strong evidences to determine the nature of deep geological bodies.