ISSN 1003-8035 CN 11-2852/P

    甘肃积石山Ms6.2级地震诱发滑坡危险性评价

    Risk assessment of landslides induced by the Ms6.2 earthquake in Jishishan, Gansu province

    • 摘要: 2023年12月18日23时59分,甘肃省积石山县发生Ms6.2地震,造成大量人员伤亡,及崩塌和滑坡等地震次生灾害的发生。基于震前震后高分辨率卫星影像,利用目视解译的灾害点和影响因子特征集构建MaxEnt模型进行地震后滑坡灾害危险性评价,研究认为:1)地震诱发滑坡灾害点主要分布在18002300 m高程带、坡度20~25°的阳坡范围内,在距道路距离1.5 km、距断裂带距离1.7 km、距地震中心距离5 km区间广布;2)由影响因子的贡献率和置换重要性、测试效益值、AUC 值和正则化训练增益值综合得到地震诱发滑坡的主要影响因子为距断裂带的距离、海拔和人口分布;3)基于构建的MaxEnt模型,得出极高和高危险区主要分布于地震烈度为Ⅷ度区,其面积为5.368 km2,占极高和高危险区总面积的77.82%,而低和极低危险区主要分布于Ⅵ和Ⅶ度区,占总研究区面积的92.80%。本文在影响因子重要性分析基础上构建MaxEnt 模型进行震区滑坡灾害危险性评价,研究结果将为震区灾后重建提供参考。

       

      Abstract: On December 18, 2023, at 23:59, a magnitude Ms6.2 earthquake occurred in Jishishan County, Gansu province, resulting in significant casualties and triggering numerous secondary geological disasters such as landslides and collapses. Utilizing high-resolution satellite imagery from before and after the earthquake, this study employs a MaxEnt model, constructed with visually interpreted disaster points and a set of impact factor characteristics, to assess the post-earthquake landslide hazard post-earthquake landslide hazard. The research conclusions are as follows: 1) Earthquake-induced landslide disasters are predominantly distributed within sunny slopes at elevations of 18002300 m and slope gradient of 20−25°, extensively across areas 1.5 km from roads, 1.7 km from fault zones, and within 5 km of the earthquake’s epicenter. The majority of the disasters occurred in cropland and loam areas with higher population density in the earthquake region. 2) The main influencing factors for earthquake-induced landslides determined by factor contribution rates, permutation importance, test benefit values, AUC values, and regularization training gain value were comprehensively determined as follows: Distance from the fault zone, Elevation, and Population density; 3) Based on the constructed MaxEnt model, it is found that there is a good consistency between the extremely high and high-risk areas of landslide disasters in the earthquake zone and the seismic intensity. Among them, the extremely high and high-risk areas are mainly distributed in the intensity VIII zone, with an area of 5.368km2, accounting for 77.82% of the total area of the extremely high and high-risk zones. The low and very low-risk areas are mainly distributed in the intensity VI and VII zones, accounting for 92.80% of the total area of the study region. This study constructs the MaxEnt model based on the importance analysis of impact factors to evaluate the landslide hazard in the earthquake area, providing references for post-disaster reconstruction in the earthquake zone.

       

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