11:00 AM - 1:00 PM
[SCG53-P04] Numerical simulation of rupture process in active faults with parallel/bent parts
Keywords:Discrete Element Method, Rupture, Resistivity Structure
Experiments with three-dimensional (3D) analog and numerical rock mass models have been tested to clarify the geological evolution of active faults and the occurrence of earthquakes. The conventional studies modelled a simple crustal structure. However, the active fault distributions are complex and possibly affect the occurrence of earthquakes. In this study, we investigated how the rock mass including weak zones, which using numerical simulation. It has greater advantages than the laboratory experiments; the numerical simulation allows us to observe the internal deformations of rock mass. In this study, we simulated the strike-slip fault motion with a small-scale rock mass model using the 3D distinct element method (DEM). Various rock mass models were tested in this simulation. For example, we test the model including two parallel active faults. Such condition is often observed in the field. We also tested another model with a long active fault but having an offset at the edge and a bending part near its center. The time-spatial rupture pattern is visualized in the numerical simulation. The distributions of fractures are compared with the actual micro-seismicity and the measured subsurface structure (resistivity structure obtained by magnetotelluric survey) along the Yamasaki fault system, Japan. As a result, the predicted fracture pattern around the two parallel faults is consistent with the observed subsurface structure. Thus, the 3D-DEM simulation is effective to understand the rupture process along faults at earthquakes. In future, the obtained rupture pattern will be available for estimation of hydraulic conductivity distributions, closely related to circulation of crustal fluid and the environment around the active faults.