2 - Uncertainties in ground motion prediction in probabilistic seismic hazard analysis (PSHA) of civil infrastructure

Abstract

Ground-motion prediction equations are a critical element of any probabilistic seismic hazard or risk analysis. The total uncertainty in a typical risk analysis is commonly dominated by the uncertainty associated with ground-motion prediction. Within the fields of engineering seismology and earthquake engineering a lot of attention has been paid to identifying intensity measures that are efficient for predicting response measures, and this efficiency is of great relevance for seismic risk analysis and the development of well-constrained fragility curves. However, the epistemic uncertainties associated with ground motions are still not adequately dealt with, and such uncertainties contribute to the overall predictability of an intensity measure, and hence of an engineering demand parameter. The present chapter provides an overview of the uncertainties that exist within ground-motion prediction and emphasises some of the main components that are not dealt with in a robust manner in current risk analyses. The chapter also highlights recent advancements as well as likely future trends associated with the treatment of uncertainty in ground-motion prediction, with a particular emphasis upon how such uncertainties influence the development of ground-motion models.