Preprints
https://doi.org/10.5194/esurf-2021-14
https://doi.org/10.5194/esurf-2021-14

  11 Mar 2021

11 Mar 2021

Review status: this preprint is currently under review for the journal ESurf.

Landslide-lake outburst floods accelerate downstream slope slippage

Wentao Yang1, Jian Fang2, and Jing Liu-Zeng3 Wentao Yang et al.
  • 1Three-gorges Reservoir Area (Chongqing) Forest Ecosystem Research Station, School of Soil and Water Conservation, Beijing Forestry University, Beijing, 100083, China
  • 2College of Urban and Environmental Sciences, Central China Normal University, Wuhan, 430079, China
  • 3Institute of Surface-Earth System Science, Tianjin University, Tianjin, 300072, China

Abstract. The Jinsha River, carving a 2–4 km deep gorge, is one of the largest SE Asian rivers. Two successive landslide-lake outburst floods (LLFs) occurred after the 2018 Baige landslides along the river. Using Sentinel-2 images, we examined the LLFs' impacts on downstream river channel and adjacent hillslopes over a 100 km distance. The floods increased the width of the active river channel by 54 %. Subsequently, major landslides persisted for 15 months in at least nine locations for displacements > 2 m. Among them, three moving hillslopes, ~80 km downstream from the Baige landslides, slumped more than 10 m one year after the floods. Extensive undercuts by the floods probably removed hillslope buttresses and triggered deformation response, suggesting a strong and dynamic channel-hillslope coupling. Our findings indicate that infrequent catastrophic outburst flooding plays an important role in landscape evolution. Persistent post-flood hillslope movement should be considered in disaster mitigation in high-relief mountainous regions.

Wentao Yang et al.

Status: final response (author comments only)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on esurf-2021-14', Anonymous Referee #1, 08 May 2021
  • RC2: 'Comment on esurf-2021-14', Anonymous Referee #2, 10 May 2021
  • EC1: 'AE comment on esurf-2021-14', Jens Turowski, 17 May 2021

Wentao Yang et al.

Wentao Yang et al.

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Short summary
The east Tibetan Plateau is an ideal place to study interactions among different geomorphic drivers. We report the impacts of two 2018 landslide-lake-outburst floods to 100 km distance downstream the Jinsha River. By using remote sensing images, we found that the 2018 floods caused many hillslopes slumping during the prolonged period afterwards. The finding could help us to obtain a holistic picture of LLF impacts and improve geomorphic models of landscape evolution.