Studying Mass Movement Sources and Potential Glacial Lake Outburst Flood at Jiongpu Co, Southeastern Tibet, Using Multiple Remote Sensing Methods and HEC-RAS Model

Abstract

Glacial lake outburst floods (GLOFs) caused by mass movement into lakes are common disaster chains in High Mountain Asia (HMA). However, the volumes of potential avalanche sources and the associated overtopping flood processes remain inadequately understood, hindering GLOF hazard assessments. We developed a comprehensive framework to quantify mass movement volumes and simulate GLOF process chains by integrating remote sensing data with hydrological models. We applied our methodology to Jiongpu Co, the largest glacial lake in southeastern Tibet. First, analysis of optical images revealed lake expansion from 2000 to 2024. Second, we assessed the volume of potential glacier avalanche using three-dimensional glacier velocities from multi-track Synthetic Aperture Radar (SAR) images. The estimated volume is 1.8 ± 0.06 × 10⁸ m³. Third, deformation on the surrounding slopes was investigated based on the time-series InSAR method, revealing a potential landslide volume of 3.5 ± 0.2 × 10⁸ m³. Next, we retrieved overtopping volumes from the potential glacier avalanche and landslide, which are 1.94 ± 0.1 × 10⁷ m³ and 9.89 ± 0.6 × 10⁷ m³, respectively. Finally, we evaluated the GLOF process chain under these two scenarios using the HEC-RAS model. Our integrated approach enhances GLOF monitoring and modeling, offering applicability to other glacial lakes for risk assessment and mitigation.