Stress rotation around faults in a 3D shear model and its relation with Coulomb stress

Abstract Synthetic data modelling is carried out with a simple model (rectangular prism) using the finite difference method, to understand the relationship between fault deformation, friction, and stress fields, specifically maximum stress rotation. Modelling with simple blocks has been carried out in previous studies, but in this research several modifications will be applied, namely: (1) displacement per year as driving force for block deformation, (2) 3D modelling over a simulation time span of 200 years, and (3) application of the half-space fault model in an elastic medium. Numerical modelling results show a sharp change in maximum stress rotation at the tips of the fault when the fault slips. This stress rotation occurs as a result of contraction/traction zones at the ends of the fault. The average value of shear stress on a fault versus the average value of Coulomb shear stress or fault shear strength is observed to be correlated with the appearance of a sharp change in maximum stress rotation. Thus, it can be used as an indicator of stress rotation on fault deformation.