Urban network resilience analysis in case of earthquakes

One of the tasks of urban and hazard planning is to mitigate the damages and minimize the costs of the recovery process after catastrophic events. The rapidity and the efficiency of the recovery process are referred to as resilience. A mathematical definition of resilience of an urban community has not yet been identified.We propose and test a methodology for the assessment of urban resilience to a catastrophic event. The idea is to merge the concepts of engineering resilience and ecosystem resilience. As first step we model a urban community by means of different hybrid complex networks, composed by human elements, i.e. the citizens, and physical elements, i.e. urban lifelines and infrastructures. As second step, we define a class of efficiency indexes on these hybrid networks. Then, we quantify the resilience of a urban system by computing these efficiency indexes before a simulated catastrophic event, after the event has occurred and during the subsequent recovery process. As a case study, we test this idea in case of simulated earthquakes in the city of Acerra, Italy.