Risk-informed evaluation of tsunami evacuation risk mitigation strategies

ABSTRACT This paper proposes the risk-informed evaluation of different tsunami evacuation risk mitigation strategies to facilitate the identification of effective strategies that are robust to uncertainties. The tsunami evacuation risk (in terms of casualty rate) is used as a quantitative performance measure to compare different mitigation strategies. An improved agent-based model is used to simulate the tsunami evacuation. A simulation-based framework is used to quantify the tsunami evacuation risk, and various uncertainties associated with the evacuation are explicitly considered. Sensitivity analysis is performed to identify critical risk factors and guide the selection of candidate mitigation strategies. The concepts of importance sampling and augmented sample-based approach are used to efficiently evaluate the evacuation risk under different candidate strategies. The risk-informed evaluation of mitigation strategies is illustrated for the tsunami evacuation in Seaside, Oregon, where strategies such as route widening, bridge retrofit, building vertical shelter, preparedness education, and evacuation drill are compared.