In the last decades there has been an increasing awareness of the importance of land stability. Land instability may induce subsidence, landslides, and other phenomena that can cause harm to human health, local property and infrastructures. The instability phenomena occur in different circumstances for a wide range of causes. A systematic monitoring of the deformation phenomena related to land, structures and infrastructures is a fundamental task for many human activities, like the maintenance of structures and infrastructures, hazard mapping, risk management, etc. The systematic deformation monitoring can hardly be performed by in-situ measurements, which are rather suitable to cover local areas. By contrast, the use of satellite-based remote sensing techniques brings the capability to cover wide area, e.g. hundreds or thousands of square kilometres.
The solution proposed to monitor subsidence and other types of land instability phenomena is the Persistent Scatterer Interferometry (PSI) technique. PSI is a radar-based remote sensing technique that provides a powerful tool to monitor deformations over very wide areas, with a high sensitivity to small deformation, e.g. see Crosetto et al. (2011) and Devanthéry et al. (2014). Several SAR satellites are available nowadays, which provide different types of coverage and resolution.
The main PSI product is given by the deformation velocity map of the covered area, which provides, for each measured point, the average deformation velocity occurred during the observed period. This map can be complemented by the deformation time series of each measured point, which describes the temporal evolution of deformation during the observed time period.
– Example_1: deformation velocity map over the airport and port of Barcelona, superposed to a SAR amplitude image (black and white image in the background).
– Example_2: example of terrain deformation caused by water abstraction. The deformation velocity is superposed to a SAR amplitude image (black and white image in the background).
– Example_3: subsidence of a road embankment. The deformation velocity is superposed to a SAR amplitude image (black and white image in the background).
– Crosetto, M., Monserrat, O., Cuevas, M. and Crippa, B. (2011), “Spaceborne Differential SAR Interferometry: Data Analysis Tools for Deformation Measurement”. Remote Sensing, 3, pp. 305-318.
– Devanthéry, N., Crosetto, M., Monserrat, O., Cuevas-González, M., Crippa, B. (2014), “An approach to Persistent Scatterer Interferometry”. Remote Sensing, 6, pp. 6662-6679.