Acta Geographica Sinica ›› 2022, Vol. 77 ›› Issue (5): 1211-1224.doi: 10.11821/dlxb202205012

• Climate and Environmental Change • Previous Articles     Next Articles

Spatial pattern and attribution analysis of the regions with frequent geological disasters in the Tibetan Plateau and Hengduan Mountains

SHEN Zexi1,2(), ZHANG Qiang1,2(), WU Wenhuan1,2,3, SONG Changqing1,2   

  1. 1. State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University, Beijing 100875, China
    2. Faculty of Geographical Science, Beijing Normal University, Beijing 100875, China
    3. National Key Laboratory of Remote Sensing Information and Imagery Analyzing Technology, Beijing Research Institute of Uranium Geology, Beijing 100029, China
  • Received:2020-11-09 Revised:2022-03-16 Online:2022-05-25 Published:2022-07-20
  • Contact: ZHANG Qiang E-mail:shenzexi@mail.bnu.edu.cn;zhangq68@bnu.edu.cn
  • Supported by:
    National Key R&D Program of China(2019YFA0606900);The Second Tibetan Plateau Scientific Expedition and Research(2019QZKK0906)

Abstract:

The Tibet Plateau and the Hengduan Mountains are located in the southwest of China, being featured by intricate landforms and deep valleys with large slopes. Due to the impacts of fluvial-induced erosions and intense geologic processes, frequent occurrences of geological disasters such as landslides, collapses and debris flows can be observed and are challenging regional sustainable development. Here we developed a random forest (RF) model to identify the geological disaster points within each sub-region. We found that the accuracies of RF models in sub-regions were all larger than 80% and can reach 91%, which evidenced modelling performance of the developed model in this study in identification of the locations with frequent occurrences of geological disasters. Meanwhile, the locations and/regions with frequent occurrences of geological disasters were found mainly in the southern part of the Hengduan Mountain area, and northeast and south parts of the Tibet Plateau, where 87% of all disaster events ranged from small scale to middle-scale. Specifically, from the view of sub-region, areas with frequent occurrences of geological disaster were 17.5 × 10 4km2, 17.4 × 10 4km2 and 27.5 × 10 4km2, respectively. Due to the spatial heterogeneities of landforms, climatic conditions and disturbance intensities from human activities, major causes of geological disasters (without considering classes of geological disasters) vary from sub-region to sub-region. For sub-region Ⅰ (south part of the Hengduan Mountain area), the main driving factors behind the small-scale and middle-scale geological disasters are impacts from constructions of roads and vibration from transportation (attribution ratio (AT) as 20.2%). Besides, main driving factors behind the small-scale and middle-scale geological disasters for both sub-regions Ⅱ~Ⅲwere impacts from vegetation coverages on slope stabilities, whose ATs are 23.6% and 27.3% respectively. Besides, the second most important causes behind small-scale and middle-scale geological disasters for sub-regions Ⅱ~Ⅲ were impacts from constructions of road and transportation (AT as 15.7%) and impacts from river erosions on slope stabilities (AT as 17%) respectively.

Key words: Tibet Plateau, Hengduan mountain area, geological disasters, random forest model, attribution analysis