Framework for Seismic Risk Analysis of Embankment Dams

This paper presents a framework for conducting seismic risk analyses for embankment dams, including the evaluation of aleatory and epistemic uncertainties and their propagation through the risk quantification. Each of the elements of a seismic risk analysis - including estimation of the seismic hazard, the assessment of the seismic fragility of an embankment for multiple potential failure modes, systems analysis, dam breach and inundation assessment, and downstream consequence analysis - is subject to multiple sources of uncertainty. In this paper we present a framework for evaluating sources of aleatory (random) and epistemic (imperfect knowledge) uncertainty in seismic hazard and seismic fragility. The framework defines aleatory and epistemic uncertainties, how they are modeled in a risk analysis, and how the uncertainties in the different parts of the analysis are combined to estimate seismic risk (e.g., annual frequency of failure) and provide insights into seismic risk drivers.