Abstract

In this study, we present a 3D magnetotelluric inversion scheme based on the concept of the radiation boundary method. In this scheme, the forward modeling and gradient computations are done in two steps. The key advantage of the proposed scheme is its ability to handle arbitrarily shaped inversion domains, defined based on the distribution of the sites, thus reducing the number of unknown model parameters that are not constrained by the data. Additionally, the two-step computation process significantly improves the accuracy and efficiency of the solutions as compared to the traditional inversion algorithm. The efficiency of the developed algorithm is tested over different synthetic data sets generated for various geological scenarios and over the USArray MT Transportable Array project, a continental scale dataset. The final inverted resistivity model for USArray data set is similar to the models reported previously but with fine resolution.