Magnetotelluric Impedance Tensor Tools (MITT)

Abstract

This manual is a first draft to guide the practitioner through MITT program. MITT program is manly constituted by four blocks: 1- Magnetotellurics impedance tensor representation (Apparent resistivity and phase curves, Impedance tensor and Mohr diagrams); 2-Probability Density Functions of different indexes which account for the dimensionality; 3- Perturbed Method to determine the ‘Phase Sensitive strike angle’ for 2D; 4- Galvanic Distortion tools for obtaining the galvanic distortion parameters, twist, shear and anisotropy (with the exception of the gain) in a general 3D case. Given that the distortion parameters cannot be determined, the method is based on a constrained stochastic heuristic method, which consists of exploring randomly the full space of the distortion parameters. The constraints imposed assume the 2D (or 1D) tendency for the shortest periods of the regional impedance tensor. In this way a unique solution fulfilling the constraints is obtained. The method is based on Romero-Ruiz and Pous (2015).