Permanent Scatterers technology: a powerful state of the art tool for historic and future monitoring of landslides and other terrain instability phenomena

This paper discusses the use of multiple image sets of SAR data acquired by past and current satellite platforms in monitoring landslides and other terrain instability issues. The basic mathematical model is presented, highlighting the critical parameters of interferometry in geological and geotechnical applications. The potential of the technology and its drawbacks related to availability of long temporal series of SAR acquisitions are also discussed. Extensive processing of many SAR scenes has demonstrated how multi-temporal data-sets can be successfully exploited for terrain monitoring, by identifying objects on the landscape that have a stable, point-like behaviour. These objects, referred to as Permanent Scatterers (PS), can be geo-coded and monitored for movement very accurately, acting as a “natural” geodetic network. The paper presents examples of applications of monitoring landslides, settlement and subsidence, using experience in Italy and Canada, and concludes with a discussion on future directions for InSAR.