Functional analysis of the urban road network in seismical emergency. GIS application on Catania city.

Road infrastructures, as it is easily known because of the dramatic seismic experiences that have recently happened in California (Loma Prieta, 1989; Northridge, 1994) and in Japan (Kobe, 1995), assume a central role in the management of the emergency both in the phases that follow the disaster, in order to guarantee a timely reaching of the affected areas with first aid means, and in the “long period” for an optimal planning of repair and rebuild operations. Only after these disasters, has a consolidated knowledge about the problem been acquired; indeed, a large number of studies on the evaluation of seismic risk have been started, also taking into account the fundamental role of the road network, mainly according to the problems of direct and indirect seismic exposure.Nevertheless, the majority of these studies have developed on large rural areas, often neglecting the similar problems concerning the management of the emergency inside affected urban centres.In this paper these problems have been faced in order to provide an operative methodology to analyse and verify the reliability of urban road networks (Lifelines), so as to guarantee safe routes for timely access to the aid coming from outside.The proposed methodology finds as a natural applicative completion the most advanced GIS software functionalities, which represent not only a powerful instrument for filing and positioning the various data to be handled, but also advanced analysis and querying systems to support decisions (DDS).The entire procedure has been applied to a district of Catania city, obtaining important results which validate the proposed methodology.