Possible locations of strong earthquakes in western Tan Shan
Ikram Atabekov
Institute ofSeismology, Zulfiyakhanum Street 3, Tashkent, 100128, Uzbekistan ; Institute ofBiophysics and Biochemistry , National University of Uzbekistan, University street 4, Tashkent, 100174, Uzbekistan
Jasur Mamarakhimov
Institute ofSeismology, Zulfiyakhanum Street 3, Tashkent, 100128, Uzbekistan
DOI: https://doi.org/10.59429/ear.v2i2.6731
Keywords: earthquake, earth crust, mathematical model, stress, geodynamics, Western Tien Shan
Abstract
The occurrence of earthquakes depends on a variety of factors generating various anomalies that are used as earthquake precursors. Mathematical modeling of the stress-strain state of the Earth's crust, verified with available instrumental data, can be used to determine the possible locations of tectonic earthquakes. For this purpose, the stress-strain state of the earth's crust of the West Tien Shan microplate has been modeled. The modern movements of the Earth's crust are modeled using the hydromechanics equations of creep motion (Stokes equations). Known GPS data served as boundary conditions. For a number of reasons at this time it is difficult to solve three-dimensional continuum equations for the Earth's crust (not exact structure of crust layers, their physical properties, etc.). Since the strong earthquakes in the region under consideration occur at depths of 15-20 km, we decided to estimate the average stress state for these depths. The Stokes equations were averaged over depth. The averaged two-dimensional Stokes equations are solved by boundary element methods. Isolines of maximum tangential stresses are constructed. Together with the energy criterion of strength, they served to determine the locations of critical stresses in the Earth's crust, where earthquakes are possible. The main horizontal stress vectors σ1, σ2 are constructed from the averaged stresses σxx, σxy, σyy. With the addition of lithostatic pressure as the third component of the main vector σ3=σver, the geodynamic state of the Earth's crust was evaluated using Anderson's method.
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