InSAR Deformation Analysis and Response Mechanism of Retrogressive Thaw Slumps in Permafrost Region of the Qinghai–Tibet Engineering Corridor

Amid global climate warming, retrogressive thaw slumps (RTSs) are increasing, posing significant risks to regional ecosystems and permafrost infrastructure. However, RTS's spatiotemporal evolution and triggering mechanisms along the Qinghai-Tibet Engineering Corridor (QTEC) remain poorly quantified. Here, we employ Small Baseline Subset Interferometric Synthetic Aperture Radar (SBAS-InSAR) to monitor surface deformation in the CHU RA MA HE–Wuli section from September 7, 2019, to July 29, 2022, and construct a multi-factor causal network based on the Convergent Cross Mapping (CCM) model. Combining InSAR deformation monitoring with optical remote sensing, we identified 238 RTSs, primarily in hilly and piedmont regions with gentle slopes(3°–6°). Spatially, deformation initiates at the headwall, while temporally, they follow cyclic thaw subsidence and frost heave, showing a delayed response to climate changes and a strong correlation with vegetation, leading to stepwise subsidence. The causal network shows that on shady slopes, land surface temperature (LST), precipitation (PRE), and normalized difference vegetation index (NDVI) exert comparable influences, whereas on sunny slopes, PRE dominates. Feedbacks between RTS deformation and LST vary with aspect, while PRE and NDVI exhibit temporal-scale separation. These findings offer valuable insights for hazard risk assessment and sustainable development along the QTEC.