Earthquake safety in historic city centres: how to plan evacuation routes by considering environmental and behavioural factors

As shown by recent Italian earthquakes, historic city centers placed in earthquake prone areas are critical scenarios for the inhabitants’ safety. They are characterized by complex and com-pact urban fabric and also by significant population presence (including tourists who are gen-erally not familiar with the urban layout). The most important role in case of earthquake emergency is assigned to streets and public spaces, that are used as evacuation paths and safe-ty areas. Current emergency management procedures are generally based on outcomes of ge-ometrical aspects (ratio between buildings heights and street width) or on built environment vulnerability analysis, but completely overlook the human factor. On the contrary, in case of earthquake evacuation, the population has to face with the post-event environment, including modifications due to the earthquake (debris, ruins, possibility to use certain paths): people should gain assembly points by preferring the less dangerous conditions in terms of damaged buildings and bottlenecks due to pedestrians’ evacuation flows. Starting from this point of view, this work provides bases for the definition a novel risk index for streets in earthquake emergency scenarios based on environmental risk level for the possible paths, positions and possible choices of evacuating population and related possible presence of slowing down in the motion process (especially in urban scenarios characterized by high population density or presence of tourists, who can be foreign with the city map). For each street along each possi-ble evacuation path, the evaluation algorithm combines: Vp as the vulnerability of buildings; Cp as the estimation of buildings damages and ruins presence along the street, in function of the earthquake intensity; Pp as the presence of risks with possible fatalities (e.g.: explosion risk); LOSp as level of service [m2/person] for evacuation speeds estimation and prediction of possible bottlenecks. Each factor is associated to a weight according to MCDM criteria. Capa-bilities of the algorithm are evaluated on a case study (the historic city center of Civitanova Marche, MC, Italy) through the application of an Earthquake Pedestrians’ Evacuation Simula-tor (EPES). Results shows how the proposed evaluation method underlines critical environ-mental conditions for man-environment interactions and suggest the definition of a map for priority interventions on building heritage in order to reduce these hazardous conditions for population