The layered tectonics and mathematical modeling of geodynamic setting of the Fergana depression (Uzbekistan)

Abstract

The geodynamic features of the Fergana intermountain depression are the presence of a rift during meridional compression of the region and the discrepancy between the location of earthquake sources and the boundaries of heterogeneities in the layers of the earth’s crust. The first feature is solved using the ideas of multi-stage plate tectonics, which provides an additional opportunity to assess the oil and gas content of the basin. However, existing hypothetical tectonic schemes are not supported by mathematical calculations. To clarify these features, we have developed a mathematical model of the stress-strain state in relation to one of the cross sections of the Earth’s crust in the Fergana depression, which has a zonally inhomogeneous density structure. The results of the mathematical model show that the presence of blocks of different densities creates displacements under the influence of horizontal compressive stresses. It is also shown that the isolines of maximum tangential stresses are located close to the boundaries of inhomogeneous zones, which indicates the presence of large errors in determining earthquake hypocenters.