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The Landslide Hazard Chain in the Tapovan of the Himalayas on 7 February 2021

On February 7, 2021, a catastrophic landslide occurred in Chamoli, India on the southern hills of the Himalayas (30.37°N, 79.73°E). About 28 × 106 m3 of landslide mass detached from the mountain face, entrained deposits in the valley and riverbed, and generated a huge debris flood along the Dhauliga...

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Bibliographic Details
Published in:Geophysical research letters 2021-09, Vol.48 (17), p.n/a
Main Authors: Jiang, Ruochen, Zhang, Limin, Peng, Dalei, He, Xin, He, Jian
Format: Article
Language:English
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Summary:On February 7, 2021, a catastrophic landslide occurred in Chamoli, India on the southern hills of the Himalayas (30.37°N, 79.73°E). About 28 × 106 m3 of landslide mass detached from the mountain face, entrained deposits in the valley and riverbed, and generated a huge debris flood along the Dhauliganga River. In this study, the geomorphological and volumetric characteristics of the disaster chain were interpreted from satellite images. The full process of the disaster chain and the erosion, deposition and flow discharge processes were reproduced using a cell‐based analysis program, Erosion–Deposition Debris Flow Analysis (EDDA). The results indicate a peak flow discharge of the debris flood at Tapovan Hydropower Station of about 25,000–28,000 m3/s. The main erosion and deposition zones are distributed along the valley floor and the Dhauliganga River, respectively. This study serves as basis for understanding the disaster chain dynamics in high mountain areas. Plain Language Summary Catastrophic geo‐disasters become more frequent in the Himalayan region due to the global climate change, and pose threats to the local residents and infrastructure. A large landslide happened in the Tapovan area in the south of the Himalayas on February 7, 2021, which triggered a large avalanche down the valley, entrained the deposits and river water, and evolved into a catastrophic debris flood in the Dhauliganga River, causing fatalities and severe damage to the local infrastructure. This study reconstructs the entire geo‐disaster process, and reveals key characteristics including the landslide source, erosion and deposition features, and the transformation of hazard types. The outcome from this study helps understand and manage the risk of catastrophic geo‐hazards in high mountain areas, especially in the Himalayas and other areas of the Tibetan Plateau. Key Points The full process of a landslide hazard chain on February 7, 2021 in the Himalayas is reconstructed using cell‐based numerical simulation The analysis explicitly explains the volume amplification and hazard type transformation in the hazard chain The erosion and deposition features during the hazard chain process are also quantified
ISSN:0094-8276
1944-8007
DOI:10.1029/2021GL093723