Local-Regional Decomposition of the Telluric Tensor

Abstract—The article considers the possibilities of using the telluric tensor in magnetotellurics, determined from the linear relationships of the electric field at the local and base points. Particular attention is paid to the local-regional decomposition of the telluric tensor, which allows separating the influence of near-surface inhomogeneities and the studied deep structures. We have adapted approaches widely used in analyzing the impedance tensor to analyzing the telluric tensor, tested on synthetic data calculated for a three-dimensional model with a deep conductive structure and a nonuniform near-surface layer. The phase tensor determined from the telluric tensor, free of surface effects, is considered. It is shown that maps of invariant parameters and polar diagrams make it possible to estimate the dimensionality of the medium, localize deep structures, and estimate their extent.