PSI - Issue 62

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Stefano Stacul, Nunziante Squeglia, Nicola Perilli / Structural Integrity Procedia 00 (2019) 000 – 000

570 Stefano Stacul et al. / Procedia Structural Integrity 62 (2024) 569–575 This is an open access article under the CC BY-NC-ND license ( https://creativecommons.org/licenses/by-nc-nd/4.0 ) Peer-review under responsibility of Scientific Board Members Keywords: landslide hazard map; landslide risk; class of attention; existing bridges

1. Introduction The Italian territory is 75% mountainous and hilly with outcrop lithotypes characterized by poor mechanical resistance, therefore landslides are widespread phenomena. In fact, 2/3 of the European recorded landslides (Herrera et al., 2018) belong to the Italian Inventory of Landslide Phenomena (IFFI database, Figure 1, left side). The IFFI database was developed by the Italian Higher Institute for Environmental Protection and Research (ISPRA), based on the data received by the District Basin Authorities and the Autonomous Provinces of Trento and Bolzano, and currently contains information on approximately 625 thousand existing landslides that cover an area of approximately 24 thousand square kilometers (8% of the entire Italian territory). According to the latest report on hydrogeological instability in Italy (Trigila et al., 2021) these data are updated to 2021 for the Autonomous Province of Bolzano, to 2018 for the Umbria Region, to 2016 for the Regions of Emilia Romagna, Friuli Venezia Giulia, Liguria, Piedmont, Sicily and Valle d’ Aosta, to 2015 for Tuscany, to 2014 for Basilicata and Lombardy, to 2007 for the remaining Regions, and the data of Calabria Region are significantly underestimated due to the fact that the recorded landslides are limited to those phenomena affecting inhabited centers and main road and railway infrastructures.

Fig. 1. IFFI Landslide database (left) and Landslide Hazard Map (right) of the Italian territory (Trigila et al., 2021)

The identification of landslides was carried out by using aerial photointerpretation (44%), collection of archival data (30%), field surveys (8%) or the integration of multiple techniques (18%). The latter approach should be recommended in the future to avoid subjectivity of interpretation which is for example a huge limit of photointerpretation methods.