The possibility of obtaining nearby 3D resistivity structure from magnetotelluric 2D profile data using 3D inversion

Currently, most of MT(magnetotelluric) data are still collected on 2D profiles. The issue that most MT researchers concern is how to invert these 2D profile data to get better results, which are closer to the real structure. Based on the analysis of 3D tensor impedance response generated from the test models and on the study of the inversion results of synthetic data and field data, we discuss the possibility of obtaining nearby 3D resistivity structure from magnetotelluric 2D profile data using 3D inversion. The results show that it is possible to interpret 2D profile data using 3D inversion method. Not only a reasonable image beneath the profile but also reasonable pictures of nearby 3D structure which can not be got by 2D inversion can be obtained using all tensor elements of the 2D profile data in the 3D inversion. The synthetic examples show that the on-diagonal elements have special effect on recovering the distribution of 3D abnormity near the profile. Therefore, all the tensor elements are suggested to be used in 3D inversion to interpret the profile data.