On stress accumulation in the lithosphere and interaction between two strike-slip faults

Abstract

The problem of stress accumulation near locked verti cal strike-slip fa ults in the lithos phere, and the interaction between two parallel strike slip faults arc cons idered. The 1"'0 parall el faults are taken to be situated in a visco-elastic half space. It is assumed that tectonic forces maintain a steady shear stress far away from the fault. Exact solutions are obtained for the displacements and the stresses in the system. It is shown that in the absence of fault slip, there would be a steady accumulation of the shear stress near the fau lts, which would lead to a sudden slip on one of the faults. resulting in an earthquake. The subsequen t chan ges in shea r stress in the neighbourhood of the fault system are investigated and exact solutions are obtained for the displacements and stresses.
 It is seen that the fau lt slip On one fault affects the accumulation of shear stress on the ot her and the effect leads to significant changes in the ra te of stre ss accumulation in the neighbo urhood of fault s if the fault s are close to each other. This int urn, affects significantly the return time bet ween co nsecutive slips on the fault. It is sho wn that the theoretical results obtained may be useful in the estima tion of seismic ris k and also in eart hqua ke prediction.