Comparison of stress field change around a fault by dynamic fault ruptusimulation using 3d-fem

When we are able to evaluate earthquake-induced stress changes of the ground around ruptured faults and adjacent faults, it will be possible to improve the prediction accuracy of the magnitude and probability of future earthquakes. Generally, the interaction between active faults is represented by static Coulomb stress changes (ΔCFF) induced by fault rupturing. In most cases, ΔCFF is calculated based on the elasticity theory of dislocation; there are few studies where it is calculated by 3D-FEM. In this study, we conducted fault rupture simulations using 3D-FEM for simple models with a planar fault plane and homogeneous bedrock and examined the influence of fault type and initial stress distribution. As a result, ΔCFF calculated by 3D-FEM became considerably larger than that calculated by the elasticity theory of dislocation. Moreover, even when a fault type and seismic magnitude were the same, the distribution domain and quantity of ΔCFF differed greatly owing to the combination of analytical parameters.