INVERSION OF MAGNETOTELLURIC DATA IN THE FAULT ZONES OF GORNY ALTAI (based on a 3D model)
V.V. Plotkin, E.V. Pospeeva, D.I. Gubin
A.A. Trofimuk Institute of Petroleum Geology and Geophysics, Siberian Branch of the Russian Academy of Sciences, pr. Akademika Koptyuga 3, Novosibirsk, 630090, Russia
Keywords: Magnetotelluric sounding, electrical conductivity, distortions and the normalization of MTS curves, surface and depth inhomogeneities, geoelectric section, recent faults, Cenozoic activity
Abstract
Results of magnetotelluric sounding (MTS) in Gornyi Altai are interpreted on the basis of a numerical model of MTS curve distortions in a 3D earth. The distortions are modelled using the Trefftz method permitting the application of models of different degrees of similarity to the test medium (depending on the available computation tools). The major advantage of this approach is demonstrated. There is no need to choose between different MTS curves (transverse and longitudinal, minimum and maximum, undistorted and distorted). Procedures of normalization of these curves become unnecessary. All recorded curves are used in full measure as input data for their inversion. Optimization of the model of the medium with regard to the distortion of MTS curves caused by surface and depth inhomogeneities improves the reliability of geoelectric sections.
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