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Vol. 26 (2023 year), No. 2, DOI: 10.21443/1560-9278-2023-26-2

Kuzina Z. Ya., Nevedrova N. N., Sanchaa А. M.
Structural features of the upper part of the section of the Gorniy Altai Uimon depression according to electrotomography data using 3D software

Determining the structure of intermountain depressions in seismically active regions at different depths is important for understanding the stages of neotectonic formation of the region and seismic hazard assessment. On the territory of the Uimon depression of the Altai Mountains in different years, measurements were carried out by deep methods of electrical exploration, such as sounding by the formation of the field and vertical electrical soundings. However, to clarify the structure of the upper part of the section, where bedrock outcrops are observed on the day surface, it is necessary to use shallow methods, for example, electrical tomography (ET). The paper discusses the results of ET data interpretation using 2D and 3D inversion when studying basement outcrops in the western part of the basin. Taking into account a priori information and the obtained models, the geological structure of the object of study has been refined. Based on the results of the interpretation of the data of electrotomography using programs of two- and three-dimensional inversion, the geoelectric structure of one of the outcrops of the basement rocks on the day surface has been determined. The immersion of the studied object in the western direction towards the adjacent outcrop of rocks of the Baratal Formation of smaller sizes located in the immediate vicinity has been established. It can be assumed that these two exits are connected at a depth of 15–20 m and, most likely, are one structure.

(in Russian, стр.10, fig. 7, tables. 1, ref 10, AdobePDF, AdobePDF 0 Kb)

Vol. 27 (2024 year), No. 1, DOI: 10.21443/1560-9278-2024-27-1

Kuzina Z. Ya., Nevedrova N. N., Sanchaa А. M.
Geoelectric model of the exposure of basement rocks to the surface in the Uimon depression of Gorny Altay based on three-dimensional numerical modeling

In the western part of the Uimon depression of the Altai Mountains, during the 2023 field season, additional measurements were carried out using electrical tomography along three profiles to clarify the structure of the area with basement rocks exposed to the surface. During the study, the results of three-dimensional inversion were obtained taking into account new electrical tomography data, and a refined geoelectric model of the study area was constructed. To verify the resulting model, 2D and 3D numerical modeling was performed with the help of which the geometric dimensions and electrical resistivity of bedrock outcrops were justified. The influence of the daytime surface topography on geoelectric sections in mountainous regions with significant differences in elevation on the earth's surface has been shown. Determining the structure of the depressions is necessary to understand the stages of neotectonic formation of the Uimon depression and the entire region, as well as to assess the seismic hazard of the Altai Mountains. In the course of further research, it is possible to trace the object to a greater depth (~100 m) using a three-electrode electrical tomography installation or alternative equipment with an increased size of the measuring-generator cable.

(in Russian, стр.8, fig. 5, tables. 0, ref 10, AdobePDF, AdobePDF 0 Kb)