On development and improvement for evaluation of exceedance probability of design basis ground motion

In the NSC regulatory guide for reviewing seismic design revised in September 2006, design basis ground motions (Ss) shall be determined by considering the following two type ground motions, 'site-specific ground motions with identification of seismic sources' and 'ground motions without identification of seismic sources'. In addition, the revised regulatory guide requires the reference to the annual exceedance probability of the DBGM Ss. As to ground motions without identification of seismic sources, a probabilistic method for ground motion evaluation has been developed to verify the validity of ground motion levels without identification of seismic sources determined by electric power companies. This method was further improved by the revision of source characterization and introduction of Monte Carlo simulation for earthquake occurrence and fault parameterization. Finally this method is to be included in a safety report of IAEA through the ISSC/IAEA Extra Budgetary Programme. (author)