Space-borne and ground-based SAR interferometry as tools for landslide hazard management in civil protection

In recent years, SAR interferometry has become one of the most popular emerging techniques for the assessment of ground displacements, and, as such, it is of great interest as a possible operational tool for civil protection institutions having to deal with landslide risk. The paper presents some of the results obtained in northern Italy during a research project aimed at testing the potentiality of the application of C-band space-borne interferometry and Ku-band ground based interferometry during different specific civil protection activities. Main research objectives were the detection of the movements of complex earth and rock slides affecting built-up areas during the 1990s, and the near real-time monitoring of a reactivated rotational earth slide over an emergency period of 15 days. Results of space-borne interferometry did qualitatively fit with the geological interpretation of the mass movements and with ground truths such as damaged buildings and in situ monitoring systems. However, this was not achieved in quantitative terms, suggesting that this technique should be used limitedly for displacement recognition and not monitoring. On the other hand, ground-based interferometry proved valuable both for a qualitative and a quantitative estimate of slope movements. Nonetheless, the research has also enabled the limitations that are still to be tackled in order to bring these systems to an operational usage in civil protection to be highlighted.