Spatial and Temporal Characterization of Landslide Deformation Pattern with Sentinel-1

Abstract

AbstractThe results of multi-interferometric processing applied to radar images acquired by the European Space Agency (ESA) Sentinel-1 constellation, obtained in the framework of the IPL (International Programme on Landslides) project n.221, are presented in this manuscript. The target area is the Hunza-Nagar River valley, a remote area in northern Pakistan. The Humarri slide, a massive landslide located along the left side of the valley, is the most active phenomenon in the area, and poses a very high risk to the Humarri village built in the lowest part of the landslide, and a threat of damming the Hispar River. The highest deformation rates (with peaks higher than 300 mm/yr) were recorded in the middle and low part of the landslide. Where the Humarri village is located, the velocity values are lower and range between −30 and −80 mm/yr. The analysis of displacement time series, spanning from February 2017 to January 2020, reveal different deformation behaviors and different onset of accelerating behaviors within the landslide body. The global coverage, the wide-area mapping capabilities, and the regular acquisitions planning ensured by the Sentinel-1 constellation, coupled with InSAR ability to deliver very precise and spatially dense information, make it possible to scan wide areas and spot unstable zones, especially where remoteness, vast areal extension, and climatic conditions make it difficult to undertake field activities.