A numerical model for cascading glacier mass flow analysis (GMFA): Erosion-deposition dynamics, phase changes, and multi-hazard chain transformations

Glacier landslide cascading hazards pose threats to communities and infrastructure, affected by complex processes including the amplification of mass flow volume through erosion and entrainment, transformation of hazard types, ice-water phase change, and enhanced mobility of the mass flow. Scientifically simulating these physical phenomena proves challenging. This study introduces GMFA (glacier mass flow analysis), an integrated numerical model that advances the field by: (1) proposing depth-averaged fluctuation energy and internal energy equations, (2) incorporating the ice-water phase change and the entrainment-deposition process, and (3) capturing their effects on mass flow runout characteristics. The model employs the finite volume method to solve the multi-physics coupled governing equations, enabling efficient large-scale simulations. The model is verified through three numerical tests covering flow dynamics, temperature evolution, and thermo-hydro-mechanical runout processes. The model is applied to analyze a hazard chain that occurred on 10 September 2020 on the Tibetan Plateau. The multi-scenario simulation results indicate an entrained mass volume of (4.95 ± 0.11) × 10⁵ m³, and a ratio of entrained mass volume to source material volume of 0.44. The solid concentration decreases from 0.6–0.7 to 0.1–0.15 with increasing runout distance, indicating a transition from avalanche to debris flood. The internal energy rises by (3–4) × 10³ kJ/m³, driving rapid ice melting from 0.1 to 0.2 to near-zero concentration. The model effectively quantifies volume amplification, ice-water phase changes, and multi-hazard transformations. This model pushes the geoscience frontier, extending computational capability from single-to multi-hazard simulations and providing a powerful tool for analyzing glacier cascading hazards.