Two-scale surface deformation analysis via the SBAS-DInSAR technique: a case study of the city of Rome, Italy

We have exploited the capability of the differential synthetic aperture radar (SAR) interferometry (DInSAR) technique, referred to as Small BAseline Subset (SBAS) approach, to analyse surface deformation at two distinct spatial scales: a low resolution, large scale, and a fine resolution, local scale. At the large scale, the technique investigates DInSAR data with a ground resolution of the order of 100m6100m. At the local scale, the technique exploits the SAR images at full spatial resolution (typically of the order of 5m620 m). The study is focused on the city of Rome, Italy, and we used the ERS-1/2 satellite radar data relevant to the 1995–2000 time period. The presented results demonstrate the capability of the SBAS approach to retrieve, from the low-resolution DInSAR data, large-scale deformation information leading to identify several sites affected by significant displacements. Our analysis permitted us to conclude that a major contribution to the detected displacements is due to the consolidation of the alluvial soils present in the area, mostly enforced by the buildings’ overload. In this case we investigated deformation phenomena at the scale of single buildings. As key result we showed that differential displacements of few mma21, affecting single man-made structures or building complexes, could be detected, thus allowing to identify sites that may potentially be involved in critical situations.