[SSS14-P13] Fault Displacement Assessment of Surface-rupturing Earthquakes for Nuclear Installations and the use of Physics-based Rupture Models
Keywords:Fault displacement, Fault displacement hazard assessment, Dynamic rupture modeling, Earthquake physics
Surface-rupturing faulting is usually expected from large earthquakes, but this phenomenon has been also observed sometimes in moderate earthquakes. The coseismic fault displacement (defined as the surface rupture offset or slip on the free-surface) associated to earthquakes can seriously compromise the safety of critical infra-structures located near faults, such as bridges, dams, railroads, pipelines, nuclear installations (NI) and nuclear waste repositories. The draft IAEA specific safety requirements (Site Evaluation for Nuclear Installations No.SSR-1, DS484) requires that the capability for surface faulting shall be assessed for the site of a NI. But current practices of fault displacement hazard assessments (FDHA) are in general very challenging and quite limited because recorded fault displacement data to develop empirical models are very sparse, as such, at present very few empirical models with large uncertainty are available for this purpose. IAEA has already recognised this issue and currently is making the effort to implement the physics-based rupture modelling in practice for FDHA. In general for seismic hazard assessments (SHA), the empirical and physics-based rupture models complement each other and all available efforts are encouraged for the nuclear safety. These efforts have been discussed through different international working group activities, being the most outstanding two international workshops on Best Practices in Physics-based Fault Rupture Models for Seismic Hazard Assessment of Nuclear Installations (BestPSHANI) in 2015 and 2018. Here we discuss the feasibility of the use of Physics-based rupture models for FDHA and presenting couple of examples of fault displacement prediction of past earthquakes.