Probabilistic Risk Analysis of Infrastructure Systems in Terms of Societal Impact

The ultimate goal of critical infrastructure systems—in fact, what makes them critical—is their role in societal functioning. Yet efforts to assess and manage risks associated with disruptive events have typically focused on damage and service interruption that result from those events, rather than their impacts on societal functioning. These effects, i.e., damage, service interruption, and interruption to social functioning, are all related, but they differ in important ways. In this paper, we extend traditional probabilistic risk analysis for spatially distributed infrastructure systems to include evaluation in terms of societal impact. We call this extension the societal impact of infrastructure disruption framework and implement it specifically for the case of household impacts of earthquake risk to the water supply and electric power systems, where household impact is estimated in terms of the implementation of household adaptations and unhappiness experienced by the individuals. A case study application in the city of Los Angeles, California, is presented to examine how many people are likely to implement different user adaptations (e.g., using a generator, going to a hotel) and how unhappy people are likely to be in response to earthquake-induced water supply and electric power outages as well as how these responses vary geographically and by earthquake scenario. These predictive insights can inform strategic decisions in infrastructure investment, sustainability planning, and emergency management, ultimately contributing to the development of more resilient communities.