Investigating building settlements via very high resolution SAR sensors

The ultimate generation of spaceborne synthetic aperture radar (SAR) sensors currently provides scientists and engineers with huge datasets of very high-resolution images that, processed via advanced differential interferometric techniques (InSAR), allow detecting and mapping ground surface displacements as well as monitoring settlements of structures and infrastructures. The present paper aims at checking the contribution that these InSAR techniques can provide for the investigation of building settlements and consequent damages in subsiding urban areas. For this purpose, a densely urbanized area in the south-western portion of the municipality of Schiedam (The Netherlands) was selected for the analysis. The subsoil in the municipality is characterized by alternating organic clay and peat layers within depths of 20 meters. InSAR data were compared with topographic leveling data available in the study area and with the results of damage surveys on the buildings. This allowed investigating the correspondence between cause (differential settlements) and effect (recorded damage) while also underlining the specific behavior exhibited by buildings according to their foundation typology. Considering the encouraging outcomes, the proposed approach holds the promise for a reliable exploitation of InSAR data and damage analysis within forecasting procedures for urban area management.