2023 Volume 79 Issue 13 Article ID: 22-13035
Predicting the position of surface faults is the first step in counter-measures for fault displacement. However, it is difficult to estimate the region of secondary faults that accompany the primary fault activity. In this paper, the occurrence region of the secondary faults was estimated based on the rock mass stress, which was evaluated by ground motion analysis using large-scale FEM. First, we formulated a method for setting the plane source in the kinematic ground motion analysis using FEM. The plane source enables us to evaluate the response near the earthquake source fault, which is important in the evaluation of secondary faults. Furthermore, a ground motion analysis for the 2014 Nagano-ken hokubu earthquake was conducted and the relationship between the surface fault and the stress and strength of the rock mass was analyzed. The results show that the local safety factor, defined as the ratio of stress to strength, can be used to estimate the region where secondary faults are likely to occur for each earthquake source model.
