SAR and optical remote sensing for urban damage detection and mapping: case studies

Remote sensing techniques have revealed a suitable monitoring tool to provide data useful for disaster studies. They allow the quick detection of damage and building collapses due to earthquakes, especially in remote areas or where the infrastructures are not well developed to ensure the necessary communication exchanges. In particular, Synthetic Aperture Radar (SAR) sensor is widely used in environmental studies due to its characteristics which allow a fairly synoptic view in almost completely weather and time independent conditions. The spatial resolution of satellite optical sensors is rapidly increasing in the last few years, reaching less than 1 meter (IKONOS and QuickBird satellites) and thus becoming a reliable tool for detecting changes of individual buildings. The combined use of optical satellite images, either at medium and high spatial resolution, and SAR data has been investigated. The results concerning the case studies of Bam and Izmit earthquakes are reported in this paper. Moreover, a comparison between the damage assessment obtained by satellite image analysis and ground survey is also shown.