基于GIS和层次分析法的沙溪流域滑坡地质灾害易发性评价

    Susceptibility evaluation of landslide hazards of Shaxi river basin based on GIS and AHP

    • 摘要: 滑坡是沙溪流域主要地质灾害类型之一,开展滑坡灾害易发性评价可为区域地质灾害防治提供数据基础和决策依据。通过沙溪流域生态地质调查,分析了滑坡灾害分布规律和影响因素之间的关系,选取岩性建造、地貌、坡度、坡向、降雨量、距河流距离和距断层距离7项指标,利用层次分析法及地理信息系统空间分析技术,开展沙溪流域滑坡地质灾害易发性评价。结果显示: 沙溪流域滑坡易发性影响因子依次为岩性建造、多年年均降水量、地形地貌、坡度、距河流距离、距断层距离和坡向; 沙溪流域滑坡灾害易发性与坡度、岩性建造、年均降水量表现出明显正相关,即坡度越大、岩性建造性质越软弱、越易风化,年均降水量越多,越易引发滑坡灾害; 滑坡灾害易发性与断裂构造、河流距离与滑坡灾害易发性呈负相关,即距离越近越容易诱发地质灾害; 流域整体以低易发区和极低易发区为主,高易发区主要分布在沙溪流域中南部、东部及东北部地区。这为沙溪流域地质灾害防治提供了基础数据和决策依据。

       

      Abstract: Landslide is one of the main types of geological disasters in Shaxi river basin, and the assessment of landslide hazard susceptibility can provide data basis and decision-making basis for regional geological disaster prevention. Based on the ecological geological survey in Shaxi river basin, the authors in this paper analyzes the relationship between the distribution law of landslide hazards and the influencing factors. Seven indicators, including lithological construction, landform, slope, aspect, rainfall, distance from the river and distance from the fault, have been selected, and analytic hierarchy process and spatial analysis technology of geographic information system are used to evaluate the vulnerability of landslide geological hazards in Shaxi river basin. The results show that the influencing factors of landslide susceptibility in Shaxi river basin are lithological formation, annual average precipitation, landform, slope, distance from river, distance from fault and slope aspect. The landslide hazard susceptibility in Shaxi river basin is positively correlated with the slope, lithological formation and annual average precipitation. The larger slope, the weaker the lithological formation, the easily weathered and the annual average precipitation is more likely to cause landslide hazards. The landslide hazard susceptibility is negatively correlated with fault structure, river distance and landslide hazard susceptibility, and the closer distance will easily induce the geological hazards. Shaxi river basin is mainly composed of low prone areas and extremely low prone areas, while the high prone areas are mainly distributed in the central south, east and northeast of Shaxi river basin. The research results proviole basic data and decision basis for geological disaster prevention and antrol in the shaxi river basin.

       

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