Stages of Strike-Slip Faulting and Block Structure Dynamics

摘要

In the paper, we present results of numerical investigation of the formation of the main fault and feathering fault structures in the sedimentary layer in strike slip of the base blocks. Main stages of the strike slip process are distinguished. The initial stage is characterized by the most gradual development of deformation, resulting in multiple discontinuities in the fault tip at the bottom of the sedimentary layer as well as in localization bands in surface layers. At the next stage the geomedium blocks are further displaced along feathering faults, with the displacement velocity considerably increasing at the moment of the fault arrival at the surface. The final stage is the coalescence of faults in the upper and lower parts and main faulting. During the process, displacements of different velocity and direction appear at the surface depending on the site and stage of faulting. The high-frequency component of surface vibrations is related to the medium fracture, arrival of discontinuities at the surface, their coalescence and main cracking. The low-frequency component is related to the development of plastic deformation and block motion. Thus, the analysis of displacement velocity and direction at different surface points can be useful for the estimation of a stage of faulting and its hazard.