2025/08/01 by Hugo Watine, Simon Daout, Jérôme Lavé +1 · 1 voice
Earth and Planetary Sciences · Environmental Science · #Climate change and permafrost #Cryospheric studies and observations #Landslides and related hazards
paper · doi:10.1016/j.rse.2025.114926
openalex publication_date 2025/08/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/22
InSAR measurements reveal widespread and high-amplitude permafrost-related solifluction movements across the Qinghai-Tibetan Plateau (QTP). This raises questions about the mechanisms driving these slope processes and, more specifically, the relationships between cyclic soil expansion during freezing and irreversible downslope motions during thawing. In this study, we develop and apply a methodology to map solifluction motions using multi-temporal Interferometric Synthetic Aperture Radar (InSAR) data and characterize their amplitudes and spatial distributions at a regional scale. This method decomposes line-of-sight InSAR time series into pluri-annual velocities and seasonally reversible surface displacements that are then inverted into motions parallel and normal to the local steepest slope. Pluri-annual downslope and subsidence velocities in the northeastern QTP are analyzed and cross-correlated with slope-normal seasonal cycles and the slope across unconsolidated sediments and indurated bedrock colluvium separately. Our analysis indicates significant downslope velocities ( > 4 mm/yr), with varying sensitivities to slope. Overall, downslope velocities exceed those expected from seasonal frost creep alone and are likely triggered by basal soil shearing during the thawing of the ice-rich layers. Downslope velocities are particularly high for indurated bedrock colluvium, which exhibit low-amplitude slope-normal seasonal cycles compared to unconsolidated sediments. We explain these differences by variations in regolith layer thicknesses, which impact the downslope deformation depths. Measurements of subsidence and amplified seasonal cycles through time indicate ongoing permafrost degradation and ice loss within the QTP, directly impacting slope stability, primarily by intensifying seasonal basal solifluction processes.