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Geoinformatika 2017; 1(61) : 33-41  (in Russian) 

MAGNETOTELLURIC RESPONSE FUNCTION OF 3D MODEL OF DEEP FAULTS

T.K. Burakhovich, O.V. Hishchuk, T.I. Prichepy

Institute of Geophysics, National Academy of Sciences of Ukraine, 32, Palladin Ave., Kyiv, 03680, Ukraine, e-mail: burahovich@ukr.net, perest-olga@ukr.net, sharapann@ukr.net

Purpose. The purpose of the paper is to calculate and analyze magnetovariation and a magnetotelluric response func­tion of the 3D object type of high conductivity regional deep fault with different angles. The authors obtained the presentation of the impedance both as a classical-tensor, and a scalar one.
Design/methodology/approach. For calculations we used a software package of 3D modeling low-frequency electro­magnetic fields, Mtd3fwd.
Findings. We have found that the deviation of the actual components of a comprehensive induction tipper of model M90 from M60 and M30 is 10% and 30%, respectively. It is concluded, with some degree of certainty, that it is possible to use leading deep faults in subvertical structures to build 3D models of real geological environments. Values ρζ and ρк (at polarization of telluric current across the top structure) stand for the relative value of the slope and the tilt direction of the modeled object, which were obtained from the scalar and tensor impedances. The values and behavior of curves ρζ are identical to curves ρк, namely ρoo. Unlike ρк, ρζ was calculated according to only one field polarization.
Practical value/implications. The deep fault with different tilt angles M90–M30 is most evident in the ratio of curves ρк (raised and lowered) directed transverse to the top structure, both relative to the level of a locally normal curve, and the level curve along the conductor. In the latter, it is difficult to determine the spatial position of anomalies, which may only be detected by the frequency shift minimum, and only directly above the conductor. The curves of phase impedance also signal relative changes in the apparent electrical resistance, with the curves directed transverse to the anomalous structure being most sensitive to it.

Keywords: deep fault, theoretical 3D modeling, conventional electrical resistivity, method scalar impedance.

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