Analysis of InSAR displacements for the slopes around Odelouca reservoir

Abstract

Odelouca is the second largest earth dam in Portugal and holds an important water reservoir. A displacement map for the slopes around the reservoir during the initial phase of the first filling was built using a multitemporal interferometric synthetic aperture radar (MTI) technique. A method based on cluster and time series analysis is proposed in order to find patterns on the obtained scatterers. The points are aggregated through a measure of the similarity between their displacement time series and form clusters, whose properties can then be evaluated. The analysis can be complemented by additional information for a better understanding of the influence on the ground of the storage of such a large amount of water. Three different patterns were identified on the data: stable scatterers, scatterers moving away from the sensor and scatterers moving towards it. A set of outliers was also detected. One of the clusters may contain points susceptible to landslide occurrence.