Geoinformatika 2020; 1(73) : 64-71

УДК 550.8

THE DIRECT AND INVERSE MAGNETOMETRY PROBLEM FOR A SET OF HORIZONTALLY SPACED ROD BODIES

T.L. Mikheeva, E.P. Lapina, N.V. Panchenko

Institute of geophysics of S. I. Subbotin NAN of Ukraine, Kiev, Ukraine, e-mail: mtat@ukr.net

Purpose. To conduct a qualitative interpretation of the initial magnetometric data, an automated system for interpreting potential fields was used. In the process of research, the following tasks were solved: based on the developed algorithms, a numerical model of the anomalous magnetometric field was constructed, a qualitative interpretation of the results was carried out, local anamaly-forming sources were modeled. The proposed algorithm makes it possible to make an express estimate for the initial approximation model, significantly reduce the number of required parameters, and bring the solution as close as possible to a real geological environment. The developed software and algorithmic software has been tested on model examples and real magnetometric data.

Design/methodology/approach. Methods based on solving the inverse problem by the selection method, an approximation design is used, which is determined by a set of three-dimensional rod bodies. The orientation of the rods is consistent with the coordinate axes. The center of symmetry of each body can move. When solving the problem, the centers of symmetry of bodies can determine the positions of geometric centers of rather complex figures. The three-rod approximation makes it possible to better describe the integral characteristics of the geological model, as evidenced by numerous model calculations. At the final stage, we used the class of three-dimensional stellar bodies, which allows the construction of smooth boundaries to describe complex structures of bodies and maximally approximate the solution to a real geological environment.

Findings. Based on the developed software, an example of approximation of the initial magnetic field is considered. The study site is located in the magnetic anomaly region, it occupies part of the Srednepredneprovsky slope of the Ukrainian shield. As a result of a three-level approximation, an a posteriori interpretation model of magnetic sources is obtained that satisfies both the observed field and a priori geological information.

The practical significance and conclusions. The considered formulation of the inverse problem can be used to solve the interpretation problems of ore geophysics. This statement of the problem can be used for express analysis of determining the center of gravity of anomalous objects, which allows us to proceed to the interpretation of three-dimensional complex geological bodies. On a practical example, this approach is considered using several approximation constructions.

Keywords: quality interpretation, magnetic field, inverse task, automated system, approximation, geological object.

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