Characteristics and triggering mechanism of Xinmo landslide on 24 June 2017 in Sichuan, China Characteristics and triggering mechanism of Xinmo landslide on 24 June 2017 in Sichuan, China

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Vol14 No.9: 1689-1700

Title】Characteristics and triggering mechanism of Xinmo landslide on 24 June 2017 in Sichuan, China

Author】SU Li-jun1,2,3#; HU Kai-heng1#; ZHANG Wei-feng1#; WANG Jiao1,3 #; LEI Yu1,3#; ZHANG Chong-lei1#; CUI Peng1,2,3*; Alessandro PASUTO4,5; ZHENG Quan-hong6

Addresses】1 Key Laboratory of Mountain Hazards and Earth Surface Process, Chinese Academy of Sciences; Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu 610041, China; 2 CAS Center for Excellence in Tibetan Plateau Earth Sciences, Beijing 100101, China; 3 University of Chinese Academy of Sciences, Beijing 100049, China; 4 Sino-Italian Laboratory on Geological and Hydrological Hazards, Chengdu 610041, China; 5 National Research Council of Italy-Research Institute for Geo-Hydrological Protection, Padova, Italy; 6 Sichuan Bureau of Surveying, Mapping, and Geoinformation, Chengdu 610041, China

Corresponding author】pengcui@imde.ac.cn

Citation】Su LJ, Hu KH, Zhang WF, et al. (2017) Characteristics and triggering mechanism of Xinmo landslide on 24 June 2017 in Sichuan, China. Journal of Mountain Science 14(9). https://doi.org/10.1007/s11629-017-4609-3

DOI】https://doi.org/10.1007/s11629-017-4609-3

Abstract】At 5: 39 AM on 24 June 2017, a huge landslide-debris avalanche occurred on Fugui Mountain at Xinmo village, Diexi town, Maoxian county, Sichuan province, China. The debris blocked the Songpinggou River for about 2 km, resulting in a heavy loss of both human lives and properties (10 deaths, 3 injuries, 73 missing, and 103 houses completely destroyed). The objectives of this paper are to understand the overall process and triggering factors of this landslide and to explore the affecting factors for its long term evolution before failure. Post event surveys were carried out the day after the landslide occurrence. Information was gathered from literature and on-site investigation and measurement. Topography, landforms, lithology, geological setting, earthquake history, meteorological and hydrological data of the area were analysed. Aerial photographs and other remote sensing information were used for evaluation and discussion. Eye witnesses also provided a lot of helpful information for us to understand the process of initiation, development and deposition. The depositional characteristics of the moving material as well as the traces of the movement, the structural features of the main scarp and the seismic waves induced by the slide are presented and discussed in detail in this paper. The results show that the mechanism of the landslide is a sudden rupture of the main block caused by the instability of a secondary block at a higher position. After the initiation, the failed rock mass at higher position overloaded the main block at the lower elevation and collapsed in tandem. Fragmentation of the rock mass occurred later, thus forming a debris avalanche with high mobility. This landslide case indicates thatsuch seismic events could influence geological hazards for over 80 years and this study provides reference to the long term susceptibility and risk assessment of secondary geological hazards from earthquake.

Keywords】High-position landslide; Xinmo landslide; Landslide mechanism; Earthquake effects; Rock fall; Debris avalanche