Построение регулярного поля скоростей Tашкентского региона на основе интерполяции данных ГНСС пунктов

Abstract

The Republic of Uzbekistan is actively developing a network of stations of the Global Navigation Satellite System (GNSS), which is an integral part of the country’s national spatial data infrastructure. Particular attention in the republic has recently been paid to the practical use of the results of GNSS measurements and geoinformation security in areas with increased seismic hazard, especially near man-caused objects. The paper considers the territory of the Tashkent region—one of the most seismically active regions of the republic. GNSS measurements are often sparse and unevenly distributed, and to refine the “block” or “continuous” tectonic models and identify patterns of modern movements in this area, a spatial velocity model is needed, which can be obtained by interpolating discrete points to the remaining area not covered by measurements. The work used measurements at 14 GNSS points for the period from 2018 to 2020. Point velocities or the so-called velocity model obtained in the GAMIT/GLOBK program made it possible to estimate horizontal point velocities, the range of which varies from 21 mm/yr to 33 mm/yr. With respect to the “stable” Eurasian tectonic plate, the values of local displacements of the area were also calculated, which can be both a consequence of the movement of microblocks and the influence of technogenic factors (mining in the area of the Angren and Almalyk points). To obtain a continuous distribution field of the horizontal velocities of the region, the method of coupled interpolation of two-dimensional vectors of the velocity field was used, implemented in the GMT (Generic Mapping Tools) program. It was found that according to the geological data of the region, the interpolation method quite accurately allows to determine the main trends in the movements of the earth’s crust in the region. A rotational movement along the Karzhantau, Kumbel and Chatkal tectonic plates has been revealed. The values of horizontal displacements of points reached a minimum value of 3 mm in the plain part, and maximum values of up to 10 mm were noted in the mountainous areas of the region. The average velocity of stations in the region was 4 mm/year.