How phase aliasing limits systematic space-borne DInSAR monitoring and failure forecast of alpine landslides

Abstract

Recent advances in satellite geodesy have improved our ability to map and monitor landslides globally with unprecedented resolution. Differential interferometry of space-borne synthetic aperture radar (DInSAR) imagery plays a major role in identifying surface displacements associated with slope instabilities and monitoring their spatiotemporal evolution. However, this technique involves several constraints that should be considered when approaching systematic and operational landslide monitoring. This work demonstrates how the effects of DInSAR temporal phase aliasing may hinder the analysis of accelerating slope deformations in alpine landslides. After defining a general framework considering the currently available satellites for DInSAR investigations, a specific accelerating slope deformation example is discussed. This study provides scientists and practitioners with important insights regarding the application of multitemporal space-borne DInSAR in systematic and/or automatic monitoring frameworks that may involve early warning applications at both local and regional scales. • The problems caused by DInSAR phase aliasing on accelerating landslides are reviewed and discussed • An example of what can happen when using only Sentinel-1 to forecast landslide failure during critical stages is presented • Insights on the application of multitemporal space borne DInSAR systematic/automatic monitoring frameworks are provided