On the combination of dual-polarization Sentinel-1 ascending/descending orbiting passes to estimate damage due to the 2016 central Italy earthquake

This study investigates the extra benefit provided by the joint use of synthetic aperture radar (SAR) polarimetric diversity and ascending/descending orbit passes to quantify postearthquake damage that occurred over the area of Amatrice, an Italian city significantly damaged by the 2016 Central Italy earthquake. First, the sensitivity of PolSAR features derived from SAR scenes collected under ascending/descending orbits to the damage is investigated. Then, the damage assessment is performed using a processing chain that consists of extracting dual-polarimetric SAR features to detect damage and, then, applying a fuzzy clustering scheme, to partition the feature outputs into damage levels. This processing chain is first separately applied to Sentinel-1 SAR scenes collected under ascending/descending orbits; then the processing outputs are merged using two different approaches. To discuss the quality of the estimated damage maps, ground information collected by surveys performed by a trained team is used. Experimental results show that the joint use of ascending/descending orbit passes improves the estimation of damage levels (up to 78%) with respect to the estimation performed using the orbiting passes separately.