INSAR MONITORING AND MAPPING OF LANDSLIDES AFFECTING TRANSPORTATION ROUTES

Recent research has shown that interferometric SAR techniques can be used to monitor deformation at landslides motion under specific acquisition conditions. Provided coherence is maintained over longer periods, as is possible on non-vegetated sites to observe surface displacement of a few cm per year. Using data pairs with short perpendicular baselines, short time intervals between acquisitions, and correcting the effect of topography on the differential interferogram, reliable measurements of surface displacement can be achieved.

This paper presents several examples using high resolution SAR images to monitor slope processes on several types of landslides near strategic transportation corridors. These landslides were triggured by several factors such as heavy rainfall, seismic activity and excessive moisture from spring melt. Since these active slides are affecting strategic transportation corridors, an integrated monitoring strategy involving InSAR and field techniques are required. For this purpose,we provide interferometrically derived images which are used to monitor current post slide motion on these sites. The images are also used in locating in-situ field monitors at specific locations on the unstable slopes, and to plan mitigation strategies. These techniques will assist in the understanding of the landslide processes, post failure mechanism and mobility and provide guidelines for integrated monitoring and mapping programs at high risk landslides sites.