Automatic movement detection by InSAR in permafrost areas. Application to the Queyras Natural Regional Park, Hautes-Alpes, France
Résumé
Interferometric Synthetic Aperture Radar (InSAR) is a method of measurement based on the phase difference between two radar images, which represent the same area but at different time intervals. The technique generates infero- grams, maps of surface deformation in two-dimensions allowing for the detection and quantification (in centimetres) of variations in distance between the target and the radar between two different data acquisitions. The present study suggests a method of automatic detection of deformation zones through the use of confidence and coherence images. The research aims to validate the methodology used by analysing the movement polygons obtained. This study was focused on the Queyras Natural Regional Park. Four different time scales are provided for the identification of four different rates of movements (cm/month, cm/2months, cm/year and cm/2years). A rockglacier inventory of Queyras was completed to provide a range of potential creeping formations. For each form several variables were described and collected in a data base. The aim was to compare the inventory with the detected movement zones by InSAR.