InSAR-based deformation analysis and multiphase simulation of glacial lake outburst cascade hazards on the Tibetan Plateau
摘要
Cascading hazards initiated by glacial lake outbursts pose major risks in high-mountain regions, yet systematic approaches for linking precursory instability to downstream cascade propagation remain limited. Here, we present an integrated framework that combines multi-orbit InSAR-derived glacier deformation observations with staged, physics-based numerical modeling to assess glacial lake outburst flood (GLOF) cascade hazards in the southeastern Tibetan Plateau. Sentinel-1 time-series observations from 2019 to 2024 reveal accelerating deformation in the glacier terminus and adjacent unstable sectors, with line-of-sight velocities of 20–40 cm year−1 in the ascending orbit and ~ 7.5 cm year−1 in the descending orbit. These observations, together with geomorphic connectivity and downstream exposure, support the identification of GL-A as the benchmark catchment for scenario-based cascade reconstruction. Under a moderate breach scenario, staged simulations indicate peak discharges of ~ 3000–3600 m3 s−1 and flow velocities exceeding 60 m s−1 in confined downstream reaches. Results show that valley confinement, slope breaks, and knickpoints exert first-order control on flow acceleration, energy dissipation, and deposition patterns, progressively reducing the influence of uncertainty in the initial breach magnitude. The proposed framework provides transferable process-level insight and a physically interpretable basis for scenario-based cascade hazard assessment in data-scarce alpine environments undergoing rapid cryospheric change.