Engineering characterization of small-magnitude earthquakes: An overview

The purpose of this paper is to present some of the background and issues that have focussed concern on the selection of a lower-bound magnitude (LBM) for use in probabilistic seismic hazard assessment. In recent years considerable effort has been spent on the probabilistic evaluation of earthquake ground shaking hazards. Engineers and earth scientists have recognized that in order to describe seismic hazard in a region, consideration must be given to the randomness of earthquake occurrences and the uncertainties associated with estimating the size and location of future seismic events. In the nuclear power industry, particular emphasis has been placed on the evaluation of seismic hazard in the central and eastern United States (EUS). The scope of this paper is limited to discussing some of the background that has focused attention on small-magnitude earthquakes (i.e., M<5.5). In addition some thoughts and recommendations are offered concerning the evaluation of a LBM for use in seismic hazard analysis