The Influence of Surface Inhomogeneities On Deep Electromagnetic Soundings of the Earth |
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Authors: | E B Fainberg B Sh Singer |
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Institution: | Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation (IZMIRAN), USSR Academy of Sciences, 142092 Troitsk, Moscow region, USSR. |
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Abstract: | Summary. Asymptotic expressions for components of the electromagnetic field of a grounded electric dipole are considered for the model consisting of a thin surface-layer overlapping a stratified medium with a highly resistive screen on the roof. It is shown that the method of spatial derivatives makes it possible to obtain proper estimates of the impedance at distances of r ≥|λ0| from the nearest edge of the surface anomaly (|λ0| being the effective depth of the field penetration in the underlying section). the magnetotelluric methods allow one to obtain the true values of impedance, provided r ≥ max {|λ0|, | /( S ?1+ Z ?0|1/2} where S is the integrated conductivity of the surface layer, is the transverse resistance of the screen, and Z ?0 is the Tikhonov—Cagniard impedance for the medium underlying the surface layer. |
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Keywords: | magnetotellurics electrical dipole subsurface inhomogeneities distortions |
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