Large, moderate, small earthquakes and seismic fortification criterion

This paper discusses the relation between two-step seismic design and the standard of probability of exceedance, and the relation of three-levels seismic ground motion parameters given by probability method and comprehensive probability method. The relative size relations of the ground motions with 2%, 10%, 63% probability of exceedance in 50 years, namely "large earthquake", "moderate earthquake", and "small earthquake", are discussed through a practical example of seismic hazard analysis. The methods to determine seismic fortification criterion are discussed.[PUBLICATION ABSTRACT]