Earth Science Frontiers ›› 2019, Vol. 26 ›› Issue (2): 312-320.DOI: 10.13745/j.esf.sf.2018.9.11

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Quick assessment of earthquake-triggered landslide hazards: a case study of the 2017 MS 7.0 Jiuzhaigou earthquake

CHEN Xiaoli, SHAN Xinjian, ZHANG Ling, LIU Chunguo, HAN Nana4, LAN Jian   

  1. 1. Key Laboratory of Active Tectonics and Volcano, Institute of Geology, China Earthquake Administration, Beijing 100029, China
    2. National Earthquake Response Support Service, Beijing 100049, China
    3. China Earthquake Networks Center, Beijing 100045, China
    4. Seismological Bureau of Shanghai, Shanghai 200062, China
  • Received:2018-01-18 Revised:2018-08-28 Online:2019-03-30 Published:2019-03-30
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Abstract: Landslides triggered by strong earthquakes in mountainous areas can cause severe casualties and also pose threats to socio-economic development in the affected region. Therefore, an effective evaluation model, not only for a quick assessment of landslide distribution, but also for identification of most hazardous areas, is needed to provide critical assistance in the deployment and execution of rescue efforts. On August 8, 2017, a MS 7.0 earthquake struck Jiuzhaigou County, Aba Prefecture, Sichuan Province. The earthquake triggered massive landslides causing casualties and property loss. After this event, we quickly analyzed the pre- and post-earthquake remote sensing images (produced by the Beijing No.2 satellite) in the affected region and interpreted the landslide distribution. Although, in some areas, the post-seismic images were unable to provide detailed interpretation of landslide due to cloud coverage, they met the primary requirements for landslide interpretation at locations of high seismic intensity where landslides mainly occurred. In total, we interpreted 194 landslides with individual area >700 m2. These landslides were mainly distributed along the long axis of seismic intensity, with an accumulative disaster area of 5.6 km2 and impact range exceeding 600 km2. Based on topography and lithology analyses of affected region, as well as peak ground acceleration data, we used the Newmark rigid block model to predict the landslide hazardous area after the earthquake. The prediction results were divided into five levels according to degree of potential danger, i.e. high, moderately high, moderate, low and very low. Comparison study shows that the predicted landslide hazard zones agreed with the actual distribution of earthquake-triggered landslides that interpreted landslides mainly distributed in areas evaluated as high danger zone, validating the effectiveness of using the Newmark rigid block model to quickly evaluate earthquake-triggered landslides. In addition, we also discussed limitations and made suggestions for future improvement in the model.

 

Key words: earthquake-triggered landslides, quick evaluation, Newmark model, Jiuzhaigou earthquake

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