Utilizzo di dati telerilevati nella mappatura e nel monitoraggio dei fenomeni franosi e nell'analisi della suscettibilità da frana

Abstract

Remote sensing as a tool for landslide mapping, monitoring and hazard assessment ABSTRACT: The recent advances in the optical satellites capabilities (e.g. high spatial resolution, stereoscopy), the development of new robust techniques based on the interferometric analysis of radar images, such as the Permanent Scatterers (PS) and the possibility of integrating these data within a Geographical Information System (GIS) have dramatically increased the potential of remote sensing for landslide investigations. The Arno river basin (Italy), with a spatial extension of about 9131 km 2 , has been chosen a as test area for the presence of a relevant number of mass movements (27270 landslides have been mapped by the institutional authorities by the end of 2004) and for its significance concerning the Italian Apennine territory. The aim of the research was to integrate the inventory maps produced through traditional methods with the information derived from the Permanent Scatterers standard interferometric analysis. The spatial significance of the PS point measures (about 600000 PS for the whole Arno river basin), also in terms of geological and geomorphological interpretation, was inferred with the help of optical satellite images and aerial-photos. This approach allowed the mapping of new unstable areas or the modification of boundaries and state of activity of existing landslides. The standard PS analysis was also employed for the validation of a statistically-based susceptibility map of the Arno river basin, through the analysis of predicted susceptibility over the areas identified as new landslides by the PS analysis. An advanced PS analysis, capable of detecting the time evolution of single important mass movements, was also applied over 4 test sites. The results for the Chianciano landslide are in particular presented. The integration of the advanced analysis with on site geotechnical monitoring confirmed the inactivity of the principal landslide body but it revealed the presence of two possible minor movements. Key terms: Landslides, Permanent Scatterers, landslide inventory map, Arno river Termini chiave: Frane, Permanent Scatterers, carta inventario, fiume Arno