One-dimensional Laterally Constrained Joint Anisotropic Inversion of CSRMT and ERT Data

In this paper, we discuss several approaches for a joint inversion of controlled source radiomagnetotelluric (CSRMT) and electrical resistivity tomography (ERT) data observed over anisotropic media. We compare results of 2D isotropic joint inversion with results of a newly developed joint 1D anisotropic inversion algorithm. The developed algorithm involves the full controlled source high frequency forward and inversion formulations without the plane wave assumption. We demonstrate that for measurements on an anisotropic subsurface the isotropic joint inversion cannot fit both datasets properly due to a high anisotropy of shallow horizons of quaternary sands and loams. The joint anisotropic inversion helps to solve this problem and highlights the advantages of a joint inversion of CSRMT and ERT data. We also demonstrate application of the laterally constrain algorithm for the anisotropic inversion. Results of the joint 1D anisotropic inversion of CSRMT and ERT data were successfully compared with existing borehole data.