ANALYSIS OF EARTHQUAKE FAULT RUPTURE PROPAGATION THROUGH COHESIVE SOIL

An improved understanding of earthquake fault rupture propagation thro ugh saturated clay would assist engineers in siting and designing faci lities to be constructed in regions where cohesive soils overlie poten tially active faults. The results from numerical analyses suggest that the finite-element method can bc applied to this class of problem pro vided that the soil's nonlinear stress-strain behavior is adequately m odeled. It was found that the height of the shear rupture zone in the overlying saturated clay soil at a specified base rock fault displacem ent depends primarily on the soil's failure strain. As the clay's fail ure strain decreases, the shear rupture zone in the clay overlying the bedrock fault propagates further at a specified base displacement. Ot her material parameters such as soil shear strength and stiffness also affect the fault rupture process, but not to the extent of failure st rain. The orientation of the shear rupture zone through the soil depen ds largely on the orientation of the underlying bedrock fault plane.