The computer code SHEAT calculates the seismic hazard (exceedance frequency of earthquakes expressed as a function of seismic motion intensity) at a site taking into account the location, magnitude, and frequency of seismic sources and the attenuation of seismic waves generated from such sources. The SECOM-2 code calculates the failure probability of each component from its response and capacity. It then uses these probilities to evaluate the failure probability of systems and the frequency of core damage accidents caused by earthquakes.