Earth Science Frontiers ›› 2023, Vol. 30 ›› Issue (3): 476-493.DOI: 10.13745/j.esf.sf.2022.12.50

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Characteristics and mitigation of coseismic geohazards associated with the Luding MS 6.8 earthquake

SUN Dong1,2,3(), YANG Tao1,2,3,*(), CAO Nan1,2,3, QIN Liang1,2,3, HU Xiao2,3, WEI Meng2,3, MENG Minghui1,2,3, ZHANG Wei1,2,3   

  1. 1. Chengdu Center of Hydrogeology & Engineering Geology, Chengdu 610081, China
    2. Sichuan Province Engineering Technology Research Center of Geohazard Prevention, Chengdu 610081, China
    3. Sichuan Huadi Construction Engineering Co. Ltd., Chengdu 610081, China
  • Received:2022-10-13 Revised:2022-11-29 Online:2023-05-25 Published:2023-04-27

Abstract:

Understanding the characteristics of geohazards and the post-seismic effect in the meizoseismal area is the key to supporting post-disaster reconstruction and disaster mitigation. In this report, the number of coseismic geohazard events following the MS 6.8 earthquake of 2022 in Luding, Sichuan, China, and their spatial distribution and controlling factors are studied based on UAV high-resolution remote sensing image interpretation, post-seismic emergency damage assessments and detailed focus-area investigation. In addition, three important risk factors for post-seismic geohazard mitigation are analyzed, and five recommendations emphasizing post-seismic reconstruction are proposed. The main findings are: (1) The coseismic geohazard events are predominantly small-scaled events and followed by medium-sized events, while large-scaled events are relatively few. These events are densely distributed along the Dadu river and its right tributary, roads, seismogenic fault and other regional faults. (2) The main controlling factors for secondary disasters are, in the order of decreasing dominance, ground motion, fault zone, terrain slope, terrain lithology and low fortification standard in the meizoseismal area. (3) The main issues in the prevention and control of post-seismic geohazards are: rainfall induced aggravation of existing structural deformation and onset of new disasters; the shattered mountains becoming source areas to trigger a chain of remote disasters; and the massive debris on channel slopes becoming a material source to cause mudslide. Accordingly, we suggest to strengthen the hazard identification system combining technology with human intervention, construct high-tech monitoring and early warning systems to monitor both hazard spots and entire slope areas, implement science-based comprehensive avoidance-and-relocation plans, raise anti-earthquake construction engineering standards in earthquake zones, and implement technical support mechanisms in building hillside houses in rural areas.

Key words: Luding earthquake, secondary geohazards, coseismic geohazards, prevention and control

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