The impact of damaging hydrogeological events on urbanised sectors: the case of 19th November 2013 in Catanzaro (Italy)

Damaging Hydrogeological Events (DHEs) are defined as the occurrence of destructive phenomena (such as landslides and floods) that can cause damage to people and goods during periods of bad weather. These phenomena should be analysed together as they actually occur because the interactions of these phenomena can both amplify the damage and obstruct emergency management. The occurrence of DHEs depends on the interactions between climatic and geomorphological features: except for long-term climatic changes, these interactions can usually be considered constant, and for this reason, some areas are systematically affected. However, damage scenarios can change; events that occurred in the past could currently cause different effects depending on the modifications that occurred in the geographical distribution of vulnerable elements. We analysed a catastrophic DHE that affected a region of southern Italy in 1951 that resulted in 101 victims and 4500 homeless individuals. The probability that a similar event will happen again in the future is assessed using the return period of the triggering rainfall, whereas the different anthropogenic factors are taken into account by means of the population densities at the time of the event and currently. The result is a classification of regional municipalities according to the probability that events such as the one analysed will occur again in the future and the possible effects of this event on the current situation.