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Alessandro Trigila, APAT - Agency for environmental protection and technical services of Italy (Italy)
Carla Iadanza, APAT - Agency for environmental protection and technical services of Italy (Italy)
Daniele Spizzichino, APAT - Agency for environmental protection and technical services of Italy (Italy)
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Starting from the second half of the last century, Italy has been characterized by a huge increase of anthropogenic pressure with infrastructures development and growth of urban settlement and texture. This kind of increase has not been always promoted by a correct and mindful land use planning and management. Scope of the present work is to estimate if the new urbanised areas have been planned in areas unstable or with a high landslide susceptibility in order to assess the contribution to the risk increase. It has been possible to calculate the percentage growth of urban areas during the period of 1960-2000 by means GIS processing techniques and comparing two different land use maps. The first map analyzed is the Land use map of Italy, published by the National Research Council and Touring Club of Italy between 1959 and 1965, developed on cadastre basis at 1:200.000 scale. The second one is the Corine Land Cover 2000 realised by the EU through photo interpretation of satellite images, at 1:100.000 scale. The features of urban areas extracted by the two land use layers has been vectorially intersected with the landslide layer contained within the IFFI geo-database. The Italian Landslide Inventory (IFFI), developed by APAT-Geological Survey of Italy and Regions/Autonomous Provinces, is a national project that aims at identifying and mapping landslides over the whole Italian territory, based on standardized criteria.
At present the inventory holds about 470,000 landslides and represents the first worldwide homogeneous and updated archive with a detailed spatial representation of landslides (www.sinanet.apat.it/progettoiffi). The study provides an estimation of increasing landslide risk of urban areas, analyzing real weight and magnitude of exposure and vulnerability for landslide risk assessment procedure keeping the same spatial hazard conditions. In more detail some case studies evidence how a lot of victims and damages could be avoided in the past by a correct land use planning and management. Concerning landslide and flood risk reduction policy, the Italian government enacted, after the Sarno catastrophe (Campania region, 1998) when more than 150 people were killed, an important law nationwide (L. 267/98). These measures impose to localize risk areas jointly with land use regulations and mitigations measure. This approach should have been determined a significant risk reduction with direct ad indirect associated costs. As soon as the update for the reference year 2006 of the Corine Land Cover (CLC2006, presently in progress) will be available, it should be possible to verify the total amount of landslide risk reduction for urban areas developed between 2000 and 2006. Due to the interaction between geological hazards and urban planning management, the analysis carried out during the present work has permitted to assess, taking into account human pressure and legal action, landslide risk trend increase/decrease in Italy during last 40 years.
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