Study on spatial distribution of earthquake-induced landslide in densely populated area of the Luding 9.5 earthquake
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摘要: 2022年9月5日,四川甘孜泸定县发生Ms6.8级地震,造成了重大的人员伤亡及经济财产损失。由于此次地震灾区多为高山峡谷地貌且植被茂密,导致人工地面排查地质灾害困难,同时基于光学影像对高植被覆盖下的震裂滑坡边界难以准确识别。因此为深入了解本次地震诱发滑坡的空间分布特征,本文首先基于获取得到的震后0.2m分辨率光学影像(DOM)进行同震滑坡目视解译,然后利用0.5m分辨率的数字高程模型(DEM)对植被层下的同震滑坡边界进行修正,同时补充解译植被层下“裂而未动”的潜在地震滑坡,再结合野外调查,最终得到此次地震诱发滑坡9248处,累计滑坡总面积约45.57km2。在此基础上分析了地形地貌、地质构造、地震因子等地质背景与地震诱发滑坡分布的关系,旨在为灾区地质灾害隐患排查、灾情评估、灾后安置选址提供重要依据,同时为灾后重建、地质灾害防治等提供重要基础和保证。Abstract: On September 5, 2022, an earthquake with Ms6.8 occurred in Luding County, Ganzi, Sichuan Province, causing heavy casualties and economic and property losses. Because the earthquake-stricken areas are mostly mountainous and canyon landforms and dense vegetation, it is difficult to investigate geological disasters on the artificial ground, and it is difficult to accurately identify the landslide boundary under high vegetation coverage by satellite images. Therefore, in order to deeply understand the spatial distribution characteristics of this earthquake-induced landslide, this paper provides a visual interpretation of the coseismic landslide based on the 0.2m resolution optical image (DOM) obtained after the earthquake, and then the boundary of the coseismic landslide under the vegetation layer is corrected by using the digital elevation model (DEM) with a resolution of 0.5m, at the same time, the potential earthquake landslide under the vegetation layer is interpreted, combined with the field investigation, 9248 landslides induced by this earthquake are finally obtained, with a total area of about 45.57km2. On this basis, the relationship between the geological background such as topography, geological structure and seismic factors and the distribution of coseismic landslides is analyzed, aiming at providing an important basis for the investigation of hidden dangers of geological disasters in disaster areas, disaster assessment and site selection for post-disaster resettlement, as well as providing an important foundation and guarantee for post-disaster reconstruction and geological disaster prevention.
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Key words:
- Luding earthquake /
- Earthquake landslide /
- Airborne LiDAR /
- Distribution law
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