Stresses and strains in a layer above moving blocks of a basement (According to mathematical and physical simulations)

Abstract

Complex tectonophysical modeling of the displacement structures in a deformable layer above the active faults in a rigid basement is carried out. These faults are supposed to be those along which a longitudinal shear (the slip on a vertical fault plane along the fault strike) or an oblique slip (strike slip with a normal or a thrust slip along a vertical or inclined fault plane) occurs. The layer being deformed simulates the sedimentary cover and the base simulates the crystalline basement. The initial stage of the process is described mathematically (calculated analytically). The stages of failure and deformation are traced by physical simulation on plastic-equivalent materials. Using finite element numerical modeling, the data are obtained for the comparison of the experimental results with the residual strains and with regions where the stresses exceed the ultimate strength. A comparative description is presented for the structures emerging above the aforementioned four types of faults. All the models are described for four amplitudes of the hanging wall movement along the fault plane in the basement: at the initial moment (analytical calculation), for amplitudes equal to 0.01H (H is the thickness of the layer), 0.1 H, and 0.5 H. The failure is compared with the plastic deformations. When doing this, in the strike-slip and in the strike-normal dip slip models, the data on the failure are taken from the experiment, whereas the boundaries of the failure in the rest of the models are yielded solely from the numerical modeling.