PEOPLE VULNERABILITY TO LANDSLIDES: AN ITALIAN PERSPECTIVE ON PREDICTABILITY AND PERCEPTION

Purpose: Frequent destructive landslides harm people every year in Italy, a country for which a comprehensive catalogue records the number of fatal landslides and the related human consequences [Guzzetti 2000 https://doi.org/10.1016/s0013-7952(00)00047-8; Salvati et al., 2010 https://doi.org/10.5194/nhess-10-465-2010, 2010; Salvati et al., 2018 https://doi.org/10.1016/j.scitotenv.2017.08.064]. Using a 16-year subset covering the period 2006-2021, we determined the dependence of the fatalities on the different circumstances of death, identifying the most hazardous behaviors in which people lost their life. The information provides real experience that can inform people awareness, based on the assumption that analyzing positive and negative examples from past events can help to cope better with future events [Stephan et al., 2017 https://doi.org/10.1007/s13753-017-0113-1; Esposito et al., 2022; https://doi.org/10.1016/j.ijdrr.2022.103440]. Methods: For the purpose, we used the information on the exact date and hour of 90 fatal landslide events and the place and circumstances in which 190 persons lost their life. We associated the fatal landslide to the forecasted daily alert level issued 24 hours before by the regional civil protection authorities in charge for hydro-geological risk. Such alerts are in four classes of increasing severity, from green to red (none, ordinary, moderate, high; https://mappe.protezionecivile.gov.it/en/risks-maps/criticality-bulletin). Results: The analysis of the monthly distribution of the landslide fatal events reveals that, both the highest number of events (19, 21%) and the highest number of fatalities (55, 34%) occurred in October, one of the wettest months in Italy [Esposito et al. 2015 Atlante italiano del clima e dei cambiamenti climatici]. Surprisingly, when analyzing the fatal events as a function of the corresponding predicted alert levels, the lowest level of alert (green) totalized the highest number of fatal events in August. Under the same alert levels, each month suffered at least one fatal landslide. Conversely, only during October fatal landslides were recorded under all the four alert levels. The result highlights that most of the fatal landslides in Italy are not related to a level of expected criticality. Despite the great efforts made by the scientific community to implement landslide early warning systems in Italy, and elsewhere [Rossi et al., 2017 https://doi.org/10.1007/978-3-319-57774-6_24; Guzzetti et al., 2020 https://doi.org/10.1016/j.earscirev.2019.102973], and the structural mitigation measures realized under different national and regional funding and regulations, the forecast capabilities and the challenge of predicting fatal landslides remain still difficult tasks. Conclusions: Under this perspective, the role of information campaigns aimed to increase people knowledge and increase risk perception are fundamental. Therefore, we quantify the role of the landslide risk knowledge that people perceive using the results of different national surveys on risk perception in relation to the potential landslide risk levels to which Italian people are exposed.