Seismic Casualty Evaluation: The Italian Model, an Application to the L’Aquila 2009 Event

Abstract

In this chapter a possible model for evaluating seismic casualties in Italy is presented. The factors influencing the evaluation are discussed and the results of the first investigations concerning their quantification are presented. The model is directly derived from the original idea of Coburn and Spence (1992); the adaptation of the model to the Italian context has been possible thanks to the data collected in the field regarding either the percentage of the victims per structural type or the lifestyle of the population obtained from the National Institute of Statistics (ISTAT). This has enabled the estimation of some of the most important parameters: the time and duration of the indoor occupancy of the population in the day, in the week, in the year. Other factors, such as the increment of population due to seasonal tourist flows or the increase of low energy seismic activity before the damaging event are discussed. Finally an application of the model to the earthquake of L’Aquila which occurred on 6 April 2009 is presented. The comparison of the official data of the human and structural damage with the simulation results show very good agreement. Considering the considerable uncertainty of the separate factors influencing the final evaluation of the casualty model, this result has to be taken with great caution and considered a favourable case rather than proof of the reliability of the model; however it represents an encouraging step toward the definition of a reliable casualty model while acknowledging that further investigation and calibration are required.