EVALUATING THE ROLE OF LAND COVER AND ITS CHANGES IN THE INITIATION OF RAINFALL-INDUCED SHALLOW LANDSLIDES IN ITALY

Purpose: Land use and land cover, and their changes, influence landslide occurrence. They act as landslide predisposing factors and affect the distribution of the vulnerable elements; therefore, they influence both landslide hazard and risk. Evaluating the role of land cover, and its change, in the initiation of rainfall-induced landslides is useful for landslide risk analysis and management. Methods: In this work, we used the recently published catalogue of rainfall-induced landslides occurred in Italy (ITALICA, [1]), which lists 6312 records with information on rainfall-induced landslides that occurred over the Italian territory between January 1996 and December 2021, with high spatial and temporal accuracy. Moreover, we used four releases of the Corine Land Cover (CLC) maps [2], namely CLC2000, CLC2006, CLC2012, and CLC2018. We associated a land cover class to each landslide in the catalogue according to its spatial and temporal features. As an example, all landslides occurred between 2016 and 2021 were associated to the CLC2018 We evaluated the number and density of landslides in each class and their spatial and temporal changes during the years. We investigated also if the spatial and temporal distributions of the landslides (e.g. annual and onthly distribution) changed in different land cover classes. Taking the Marche region (central Italy) as a hot spot (having this region 1220 records in the national catalogue), we analyzed if the rainfall triggering conditions of the landslides changed in the different land cover classes. Results: We observed that around half of the landslides in the Italian catalogue occurred in agricultural areas. However, in the recentmost years, the percentage of landslides occurred in both urbanized and forested areas ncreased considerably. The monthly distribution of landslides is different: in agricultural areas the landslides are homogenously distributed in DJF, MAM, and SON; in forested and seminatural areas more than half of the evens occurred in JJA and SON. Regarding the Marche region, two thirds of the landslides occurred in agricultural areas. The landslide triggering conditions are different: overall, less rain is needed to trigger a landslide in agricultural areas then in forested and semi-natural areas. Conclusions: We observed spatial and temporal changes in the distribution of landslides in the Corine land cover classes in Italy, and in the landslide triggering conditions. These preliminary findings can be used future evaluation of changes in landslide initiation in response to projected land cover changes. References 1. Brunetti et al. 2023 ITALICA (ITAlian rainfall-induced LandslIdes CAtalogue) (Version 1) [Data set]. Zenodo. https://doi.org/10.5281/zenodo.7646106 2. https://land.copernicus.eu/pan-european/corine-land-cover, last accessed 20/02/2023