Layered Tectonics and Mathematical Modeling of the Geodynamic Setting of the Fergana Depression (Uzbekistan)

Abstract—

The geodynamic features of the Fergana intermontane depression are the presence of rifting during regional meridional compression and the discrepancy between the location of earthquake sources and boundaries of inhomogeneities in crustal layers. The first feature is solved using the ideas of multistage plate tectonics, which also makes it possible 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 with respect to one of the cross sections of the crust in the Fergana depression, which has a zonally inhomogeneous density structure. The results of the mathematical model show that the presence of blocks with different densities creates displacements under the impact 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 large errors in determining earthquake hypocenters.