NHESSD Natural Hazards and Earth System Sciences Discussions NHESSD Nat. Hazards Earth Syst. Sci. Discuss. 2195-9269 Göttingen, Germany 10.5194/nhess-2019-90 Landslides distribution at tributaries with different evolution stages in Jiangjia Gully, southwestern China Tian Xia Fei 1 2 3 Li Yong https://orcid.org/0000-0002-5680-3131 1 2 Tian Quan Yan 3 4 Su Feng Huan 1 2 Key Laboratory of Mountain Hazards and Surface Process, CAS, Chengdu, 610041, China Institute of Mountain Hazards and Environment, CAS, Chengdu, 610041, China University of Chinese Academy of Sciences, Beijing 100049, China Cold and Arid Region of Environmental and Engineering Research Institute, CAS 23 04 2019 2019 1 23 Copyright: © 2019 Xia Fei Tian et al. 2019 This work is licensed under the Creative Commons Attribution 4.0 International License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/4.0/ This article is available from https://nhess.copernicus.org/preprints/nhess-2019-90/ The full text article is available as a PDF file from https://nhess.copernicus.org/preprints/nhess-2019-90/nhess-2019-90.pdf

<p>Jiangjia Gully (JJG) is known for its high frequency and variety of debris flows, especially the intermittent surges of various flow regimes and materials. Observation indicates that the surges come from various tributaries with different landslides activities. In this study, 81 tributaries of JJG are taken from DEM with 10&thinsp;m grid cells, and the hypsometric curves are used to characterize their evolution stages; five stages are identified by the evolution index (EI, the integral of the hypsometric curves) and most tributaries are in relative youth stage with EI between 0.5 and 0.6. Then 908 landslides are interpreted from Quickbird satellite image of 0.61&thinsp;m resolution, and it is found that LD (LD&thinsp;=&thinsp;landslides number in a tributary/the tributary area) increases exponentially with EI, while LA<sub>p</sub> (LA<sub>p</sub>&thinsp;=&thinsp;landslides area in a tributary/the tributary area) fluctuates with EI, meaning that landslides are inclined to occur in tributaries with EI between 0.5 and 0.6, and thus these tributaries are the main material sources supplying for debris flows.</p>

 National Natural Science Foundation of China 41471011 2016YFE0122400