ABSTRACT
The dynamic fault rupture simulation was conducted using the three dimensional finite difference method without giving a priori rupture starting area and rupture stopping area by changing the coefficient of friction or changing the frictional constitutive law. It was conducted on condition that the shear rigidity was changed along the fault plane and that the shear stress on the fault plane was loaded by forced displacement. In this study, induced shear stress in the fault layer by the forced displacement was larger at the center part because of higher shear wave velocity and stress was smaller at the outskirts part because of lower shear wave velocity. The ununiform shear stress distribution caused spontaneous fault rupture starting from the central part in spite of constant frictional condition in this layer. The fault rupture was spontaneously stopped after the rupture spread up to around 10km in the x-direction without giving a priori rupture stopping area by frictional condition. It was consistent with previous studies in the fault rupture process that the rupture velocity was 3～3.5km/s at most. It was not incompatible that the stress drop was about 2MPa. We could estimate the near fault ground motion for our model fault by using this dynamic rupture simulation. The slip velocity time function directly calculated by the dynamic fault rupture simulation was consistent with previous study.
