Arresting mechanism of earthquake faulting

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Geometrical complexity of earthquake faults will be a manifestation of mechanical inhomogeneities of the earth's crust. It will therefore be closely associated with the arresting mechanism of dynamic earthquake faulting. A detailed study was carried out on the relation between the complexity of earthquake faulting and the arresting mechanism of faulting.High-pressure fluids existing in a fault zone can promote an earthquake rupture. The effect of pore-fluids on the earthquake rupture, especially on the arresting of rupture, is also studied in this research project.We developed new numerical methods to simulate an arbitrary-shaped rupture on the basis of boundary integral equation methods (BIEM). One of the difficulties in such a BIEM treatment is the evaluation of hypersingular integrals. We first made a formulation from the regularization approach, and derived a set of non-hypersingular boundary integral equations, both elastodynamic and elastostatic, for the analysis of arbitrarily s … More haped 2-D cracks. We carried out the simulation of dynamic cracks with side-branches. The results of the simulations show that the stress concentration at the propagating tip of the main crack is lowered by the presence of the side-branches. This suggests that the branching of the crack plays an important role in the deceleration and arresting mechanism of earthquake rupturing.The method based on the regularization approach is somewhat complicated, so that we next developed a more efficient method taking finite parts of hypersingular integrals. Numerical simulation of unsteady dynamic propagation of arbitrarily shaped 2-D cracks will be easily carried out using this method.It is well known from field observations that a fault zone is generally regarded as fluid conduit. If an earthquake rupture takes place, non-linear mechanical interactions occur between the fault fluids and the rupture. Our analysis of the interactions showed that the fluids can a factor to arrest the earthquake rupture if there is a high inhomogeneiry in the distribution of the fluid in the fault zone. Less