Earth Science Frontiers ›› 2021, Vol. 28 ›› Issue (2): 125-139.DOI: 10.13745/j.esf.sf.2020.9.11

Previous Articles     Next Articles

Tectonic interpretation of the main paleoseismic landslides and their distribution characteristics in the Chenghai fault zone, Northwest Yunnan

HUANG Xiaolong1(), WU Zhonghai1,*(), LIU Feng2,3, TIAN Tingting1,4, HUANG Xiaojin5, ZHANG Duo6   

  1. 1. Key Laboratory of Neotectonic Movement & Geohazard, Institute of Geomechanics, Chinese Academy of Geological Sciences, Beijing 100081, China
    2. Institute of Geomechanics, Chinese Academy of Geological Sciences, Beijing 100081, China
    3. Ministry of Natural Resources Key Laboratory of Deep-Earth Dynamics, Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China
    4. School of Earth Sciences and Resources, China University of Geosciences (Beijing), Beijing 100083, China
    5. Research Institute for Smart Cities, Shenzhen University, Shenzhen 518060, China
    6. Capital Normal University, Beijing 100048, China
  • Received:2020-07-30 Revised:2020-08-31 Online:2021-03-25 Published:2021-04-03
  • Contact: WU Zhonghai

Abstract:

The Chenghai fault zone, located at the northwest end of the Red River fault zone and the east side of the Northwest Yunnan fault depression zone, has significant Quaternary activity. Geological disasters occur frequently along the fault where basin range and high valley landforms are apparant. Based on visual interpretation and field investigations, a total of 940 landslides were found along the Chenghai fault zone, which included 61 giant landslides, 125 large landslides, 316 medium-sized landslides, and 438 small-sized landslides. Among them, 32 giant and 61 large landslides are located on the fault scarps and fault triangles within about 5 km from the footwall of the Chenghai fault zone. These large scale landslides often have long sliding distance, high speed and long-distance debris flow as the main characteristics, and belong to the paleoseismic landslides triggered by earthquakes in the Chenghai fault zone. According to the investigation of the main paleoseismic landslides in this area, these landslides are mainly distributed in the areas east of the Jinguan and Chenghai Basins, south of the Qina Basin at the intersection of the Jinsha River and the Chenghai fault zone, and across the western Midu Basin. They are obviously controlled by the activities of different sections of the Chenghai fault zone. The giant and large paleoseismic landslides are mostly developed at the north end of the Chenghai fault zone where it has the highest vertical activity. According to the analyses of the late Cenozoic activity of the Chenghai fault zone and crustal deformation characteristics of the southeastern margin of the Tibetan Plateau, it is the clockwise rotation of the Northwest Yunnan fault depression zone that led to more intense fault activity and more frequent earthquakes. As a result, more paleoseismic landslides occurred at the end of the Chenghai fault zone. The power of the clockwise rotation of the Northwest Yunnan fault depression zone comes from the clockwise rotation of the Sichuan Yunnan inner arc zone and the strike-slip pull-apart of the Nantinghe, Wanding, and Litang faults.

Key words: northwest Yunnan, Chenghai fault zone, palaeoseismic landslide, clockwise rotation

CLC Number: