On Features of Transient Electromagnetic Sounding of Horizontally-Inhomogeneus Media (Based on Physical Modelling Results).

Certain features of electromagnetic transient exhibitions excited by controlled source (transient sounding - TS) are considered. The investigations are conducted by physical modelling method. Field anamalously strong distortions associated with near surface and deep inhomogeneities are modelled. Two types of distortions are revealed: Sign inversion of the field measured near the high conductive quasi-2D inhomogeneities and variation of the magnetic field transition when the measuring loop is near the edge of inhomogeneity of any conductivity. Application of electromagnetic sounding systems with ceasured value averaging and relating the results in some cases to a receiver loop and in other cases - to the center of the set (depending on the inhomogeneity type) allows to substantially attenuate anomalously strong distortions of the electromagnetic field.