2025 Dingqing catastrophic landslide induced by frost heaving on high hillslopes in the southeast Tibetan Plateau, China
摘要
At about 21:30 pm on Sunday, 1 June 2025, a catastrophic landslide destroyed a temporary settlement of seasonal Cordyceps (medicinal fungus) collectors in Muta Town, Dingqing County, Tibet. About 2.0 million m3 of rock detached from the crest of the snow-covered mountains area, which resulted in 3 deaths and 7 people missing. This landslide and the severity of its effects were promoted by three concurrent phenomena: development conditions, time, and location. This event raised great concern both in China and beyond, and it exposed our lack of understanding of the landslide types induced by frost heave. This study uses extensive field investigation, satellite remote sensing, UAV aerial photography, rock mechanics testing, and numerical simulations to determine the deformation history, failure modes, and dynamic process of the landslide. The preliminary results suggest that the landslide source area experienced long-term deformation with the development of significant transverse cracks distributed along bedding planes. An exposed reverse slope was formed by the denudation of the strata of a Z-shaped fold, which had undergone frequent freeze-thaw cycles damage and finally triggered the landslide. The maximum landslide velocity was 30 m/s, the maximum accumulation thickness reached 24 m, and the landslide essentially ceased movement after 120 s. This paper reveals the failure mechanism whereby frost heave in high-altitude seasonal permafrost regions triggers slope instability in degraded red strata areas. Our findings provided new insight into landslide failure caused by frost heave damage on high hillslopes in alpine mountain areas.