U.S. Regulatory perspective on seismic design ground motion, a uniform reliability spectrum

In 1996, the U.S. Nuclear Regulatory Commission (NRC) amended its regulations to update the criteria used in decisions regarding nuclear power plant siting, including geologic, seismic and earthquake engineering considerations for future applications. As a follow-on to the revised siting regulations, it is necessary to develop state-of-the-art recommendations on the design ground motions commensurate with seismological knowledge and engineering needs. The paper will review the revised seismic and geologic siting criteria, and the scope of the work associated with the development of design ground motion, indicate the direction the recommendations are taking, present preliminary results, and discuss some implications. (author)