Three-dimensional and long-term landslide displacement estimation by fusing C- and L-band SAR observations: A case study in Gongjue County, Tibet, China

Recently, a large number of synthetic aperture radar (SAR) images has been introduced into landslide investigations with the growing launch new SAR satellites, such as ALOS/PALSAR-2 and Sentinel-1. Therefore, it is appropriate to develop approaches retrieve three-dimensional (3D) displacements long-term (> 10 years) displacement time series investigate spatio-temporal evolution creep behavior landslides. In this study, approach for estimation 3D landslides, based on fusion C- L-band observations, presented. This method applied map (nearly 12 landslides in Gongjue County, Tibet China; four sets from different platforms (i.e., ascending ALOS/PALSAR-1, C-band descending ENVISAT, Sentinel-1 datasets) covering period January 2007 November 2018 were collected exploited. First, assumption that moves parallel its ground surface used produce rates by fusing images, which optimal sliding direction each pixel slope well estimated. Then, time-series between October estimated recovered ALOS/PALSAR-1 images. order fill gap nearly years Tikhonov regularization (TR) developed establish observational equation. Moreover, solve problem arising wavelengths, incidence angles flight directions, measurements are both projected achieve unified datum. Our results suggest maximum study area vertical east-west directions December 2016 greater than 70 80 mm/year, respectively, 2D reveal patterns movement characteristics all detected not identical area. Specifically, successfully revealed spatiotemporal block Shadong landslide, showed first cumulative exceeds 1.3 m 2018. kinematic possible driving factors investigated using results, coupled hydrological unidimensional constitutive models rocks.