A SEISMIC RISK ASSESSMENT FRAMEWORK FOR LOSS ESTIMATION OF CRITICAL INFRASTRUCTURE – HOSPITALS CASE

Abstract

In this paper, a framework developed for the seismic risk assessment and loss estimate of the Health-Care sector is described. The methodology herein presented derived from a wider study that refers to a multi-hazard (earthquake, hurricane, flood, landslide, rockfall, avalanche) and multi-asset (healthcare and energy infrastructure). The loss estimate is based on the probabilistic modelling of hazards and asset vulnerability and an overall assessment of the impact generated from the suffered damage treated as a deterministic consequence of it. Specifically, the total impact computation is based on the combined analysis of different aspects, such as physical damages, service reduction, and social impact. For the sake of completeness also the impact is evaluated per each aftermath level. It must be pointed out that in so doing the loss computed per each impact can be ensured as hazard independent. An important role in the impact evaluation is also played by resilience. A simplified evaluation of preparedness and resourcefulness at asset and local level is performed to originate a set of resilience-based coefficients which, in turn, are used to influence the evaluation of the loss per each impact component and level of damage. Finally, the Expected Annual Loss (EAL) is provided as the exponential relation between the probability of damage occurrence expressed as mean annual frequency, and the loss, expressed in economic terms. So, this relation can define the properties of damage occurrence and loss of each possible event. Thanks to the quantitative approach of the framework it can be seen how each risk aspect influence the curve properties, such as the horizontal stretch due to resilience influence on the loss degree and the vertical stretch due to vulnerability effect on the damage occurrence