Empirical susceptibility, vulnerability and risk analysis for resilience enhancement of urban areas to terrorist events

The worldwide progressing urbanization increases the need to consider threats like terrorism or natural disasters when planning or redesigning urban areas. The paper shows how to assess and mitigate terrorism risks in a systematic way using historical event data on urban plan level. Based on multiple event data, within a risk approach, quantities are derived that measure averaged susceptibilities, vulnerabilities and risks for buildings and infrastructure in the context of urban planning. The empirical approach allows for local scaling factors for frequency of events, e.g., due to physical accessibility, and for consequences, e.g., due to physical counter-measures. The paper discusses the input data necessary for statistically sound analyses, in particular, the accuracies of the quantities as well as deep uncertainties. To this end, it determines distributions for the frequencies and consequences, in particular, introducing a modified Pareto distribution. The application to a sample urban area demonstrates how the analysis results lead to a more resilient scenario using the analysis and selecting resilience improvement options. It is shown that the empirical analysis motivates more detailed additional engineering-simulative approaches for resilience improvement through averaging susceptibility, vulnerability and risk assessments by assuming multiple spatially distributed events