Land subsidence is a common natural hazard striking extensive areas worldwide that can be triggered by geological
and/or anthropogenic factors. In many cases, subsidence affects urbanized areas and causes remarkable economic loss.
Adopted policies and solutions for land subsidence management can be various, but despite this variability, where
mitigation methods have to be put into practice, the detailed mapping, characterization and simulation of subsidence
have to precede their design and implementation. In the framework of the Terrafirma Project (www.terrafirma.eu.com),
the exploitation of Persistent Scatterer Interferometry (PSI) for subsidence analysis has been promoted. Satellite
interferometry, thanks to its wide spatial coverage and its millimeter accuracy, is ideally suited for the measurement of
the spatial extent and magnitude of surface deformations associated with subsidence phenomena. Three validated case
studies, where subsidence is caused by different factors, are presented here: the wide area of Rome (Italy), the Gioia
Tauro plain (Italy) and the Kalochori village (Greece). These case studies have been selected with the aim of showing
the main activities that must be covered and performed when dealing with geohazard investigations, i.e., mapping,
monitoring and modeling. Particularly, data from ERS1/2, Envisat and Radarsat satellites have been exploited to map
ground deformation in the area of Rome and to monitor the ground subsidence in the Gioia Tauro plain. Due to the large
availability of geological and geotechnical data, the area of Kalochori village has been selected to model the land
subsidence by applying Finite Element simulation. Results of the simulation have been validated with PSI techniques.