LATERAL CONDUCTIVITY VARIATIONS AS INFERRED FROM GLOBAL MVS AND MTS DATA BY CORRELATION OF FIELD COMPONENTS
V.V. Plotkin
Institute of Geophysics, Siberian Branch of the RAS, 3 prosp. Akad. Koptyuga, Novosibirsk, 630090, Russia
Keywords: Electric and magnetic modes, global EM sounding, impedance, tipper, MVS, MTS, lateral conductivity variations
Pages: 557-566
Abstract
Simulation of the global electromagnetic field as a sum of related electric and magnetic modes simplifies the solutions to both forward and inverse global EM problems. The forward problem (for EM field) is solved with only horizontal or only vertical field components measured on the Earth's surface, and the inverse problem (for conductivity inside the Earth) is solved by fitting of the correlated surface horizontal and vertical components. The component correlation approach to lateral conductivity variations inside the Earth requires neither source modeling nor computing source dependences of impedances and tippers. Processing measured global Sq variations with the new method tentatively indicates the presence of lateral variations in diurnal-period skin depth and in skin-depth average conductivity.
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