Seismic Probabilistic Risk Assessment
PRA is a process of probabilistic evidential and inferential analysis of the response of events, systems, or activities to different challenges based on the fundamental rules of logic and plausible reasoning. The risk measure is most often a frequency whose uncertainty is represented by a probability distribution. This is often referred to as the “probability of frequency” format. Frequency is based on observations, which could include something as abstract as a thought experiment, whereas probability calibrates the credibility of the frequency based on the supporting evidence. PRA is a thought process for answering the three basic risk questions stated previously.
EPRI