STUDY ON SUCCESSIVE LANDSLIDE DAMMING EVENTS OF JINSHA RIVER IN BAIGE VILLAGE ON OCTORBER 11 AND NOVEMBER 3, 2018

A large-scale landslide occurred in Baige village, at the border between Tibet Autonomous Region and Sichuan Province, on October 11, 2018. The sliding mass detached from a high-elevation mountain ridge, then dammed the Jinsha River impounding a barrier lake. This initial lake drained naturally. Afterwards, on November 3, a second landslide involved with a large mass of loose material from the first event blocked the river again, inducing a 50 m high dam and a barrier lake with a capacity of 500 million cubic meters. In order to alleviate the dangers of potential dam-breach flood, the artificial spillway was constructed allowing controlled breaching until November 13. However, downstream flooding still cause a major loss of property and damage, covering a large area of Sichuan Province and Yunnan Province. Extensive on-site investigation, combined with historical satellite images interpretation, InSAR monitoring, UAV aerial photography and ground deformation monitoring techniques, was conducted in this paper, to analyze the historical deformation of the study area and the evolutional characteristics of these two events. Based on that, the emergency measurements after each event have been developed, and the implementation of spillway was secured by monitoring and early-warning work at site. The successive landslides damming the Jinsha River presents a good example to study the emergency response and mitigation plan for similar cases in the future.