Evaluation of building damages induced by landslides in Volterra area (Italy) through remote sensing techniques

This paper aims to detecting terrain movements in landslide-affected and landslide-prone zones and their damaging effects on the urban fabric. The case study is the Volterra area in Tuscany region (Italy), covers about 20 km2 and is extensively affected by diffuse slope instability. Firstly, the spatial distribution and types of the landslides were studied on the basis of the geological and geomorphological setting coupled with a geotechnical monitoring. Secondly, satellite SAR (Synthetic Aperture Radar) images acquired by ENVISAT and COSMO-SkyMed sensors respectively in 2003–2009 and 2010–2015 and processed with Persistent Scatterer Interferometry (PSI) techniques, were exploited. In particular, these satellite radar data combined with thematic data and in situ field surveys allowed the improvement of the geometric and kinematic characterization of landslides, as well as allowing a deformation and damage assessment to be undertaken on built-up zones. The classification of damage degree and building deformation velocity maps of the study area were also evaluated through PSI displacement rates. Furthermore, as a single building-scale analysis, maximum differential settlement parameters of some sample buildings were derived from radar measurements, and then cross-compared with constructive features, geomorphological conditions and with field evidences of known landslide areas. This work allowed the correlation of landslide movements and their effects on the urban fabric and provided a useful stability analysis within future risk mitigation strategies.