若羌南部山区崩塌灾害易发性评价——基于相关性分析的信息量模型

Risk Assessment of Collapse Disasters in the Southern Mountainous Areas of Ruoqiang County-an Information Quantity Model Based on Correlation Analysis

若羌县南部山区地质灾害研究程度较低,区域防灾减灾工作面临重大挑战。通过对若羌县南部山区特别是阿尔金山地区崩塌灾害的形成机理、成灾模式、影响因素等进行分析。对选取的10个因子中贡献程度较低的坡面曲率和地貌类型两项因子进行删除,保留剩余的坡度、坡向、地形起伏度、工程地质岩组类型、NDVI划分为基本因素,将道路距离、水系距离、断层距离等8个因子作为评价指标,选取栅格单元为基础评价单元进行信息量计算,构建信息量模型对研究区崩塌灾害易发性进行评价与区划。结果表明:(1)区域内划分为高、中、低、非易发区,其中高易发区总面积391.48 km^(2),占若羌县总面积的0.20%,占阿尔金山区面积的35%,共发育崩塌95处;中易发区总面积16 375.14 km^(2),占若羌县总面积的8.26%,占阿尔金山区面积的15%,共发育崩塌11处;低易发区总面积31 455.63km^(2),占若羌县总面积的15.88%,占阿尔金山区的25%,共发育崩塌灾害5处;非易发区总面积149 906.50 km^(2),占若羌县总面积的75.66%,占阿尔金山区的25%;(2)ROC曲线以下面积为0.931,说明易发性预测结果良好;(3)人类工程活动(以矿山道路建设、开发等)对崩塌灾害易发性影响最明显,距离道路小于200 m区域为地质灾害易发区,距离河流小于100 m区域易发生地质灾害,坡度在40°~50°区域地质灾害发生较明显,地形起伏度较大区域为地质灾害高发区,工程地质岩组类型为坚硬-较坚硬块状、较坚硬软弱、软弱互层状以砂岩、砾岩、泥岩为主的碎屑岩岩组及坚硬-较坚硬片状以片岩为主变质岩岩组,对地质灾害发生具一定影响。坡向、断层及NDVI在本次工作区对地质灾害影响相对较小。评价结果可为区内危险性、风险评价及区划等方面提供理论依据,为当地防灾减灾管理、地质灾害风险管控、国土空间规划和用途管制、新农村和重点工程规划建设服务等提供基础依据。

The southern mountainous area of Ruoqiang County,especially the Altun Mountain area,is an important gathering place for mineral veins in Ruoqiang County and even the entire Bazhou region.It is a bridgehead and strategic location for the new round of local strategic mining operations,which has made it an important area for the development of collapse disasters,seriously threatening the safety of local people's lives and property,and seriously hindering the development of the new round of strategic mining operations in this area.At present,due to the low level of research on geological hazards in the region,disaster prevention and reduction work is facing significant challenges.On the basis of the 2023 Central Finance funded project“Geological Disaster Risk Investigation and Evaluation Project in Ruoqiang County”,this article analyzes the formation mechanism,disaster mode,and influencing factors of collapse disasters in the southern mountainous areas of Ruoqiang County,especially in the Altun Mountains area.Based on the Pearson correlation coefficient method,influential factors with strong correlation are selected,and the contribution comparison method-Correlation Attribute Evaluation(CAE)is used to compare the contribution of the influencing factors.After deleting the two factors of slope curvature and landform type with lower contribution in the selected 10 factors,the remaining slope,aspect,terrain undulation,engineering geological rock group type,and NDVI are retained as basic factors.Road distance,water level,and NDVI are divided into basic factors.Eight factors such as system distance and fault distance are used as evaluation indicators,and grid units are selected as the basic evaluation units for information content calculation.An information content model is constructed to evaluate and zoning the susceptibility of collapse disasters in the study area.The results show that:(1)the region is divided into high,medium,low,and non prone areas,with a total area of 391.48 km2 in high prone areas,accounting for 0.20%of the total area of Ruoqiang County and 35%of the area of the Altun Mountains,with a total of 95 landslides developed;The total area of Zhongyifa District is 16375.14 km^(2),accounting for 8.26%of the total area of Ruoqiang County and 15%of the area of Altun Mountain Area,with a total of 11 landslides developed;The total area of the low risk area is 31455.63 km^(2),accounting for 15.88%of the total area of Ruoqiang County and 25%of the Altun Mountain area,with a total of 5 landslide disasters developed;The total area of non prone areas is 149906.50 km^(2),accounting for 75.66%of the total area of Ruoqiang County and 25%of the Altun Mountains.(2)The area below the ROC curve is 0.931,indicating good susceptibility prediction results.(3)Human engineering activities(mainly mining and road construction,development,etc.)have the most obvious impact on the susceptibility of collapse disasters.Areas less than 200 m away from roads are prone to geological disasters.Secondly,areas less than 100 m away from rivers are more prone to geological disasters.Areas with slopes of 40-50°have a more obvious impact on the occurrence of geological disasters.Areas with larger terrain undulations are also high-risk areas for geological disasters.The types of engineering geological rock formations are hard to harder hard block like,harder to weak,and weak interlayered with sandstone,conglomerate,mudstone as the main clastic rock formations and hard to harder sheet like metamorphic rock formations with schist as the main metamorphic rock formations.Slope orientation and distance also have a certain impact on the occurrence of geological disasters.The impact of fault distance and NDVI on geological hazards in this work area is relatively small.The evaluation results are basically consistent with the field investigation,and the results can provide theoretical basis for hazard assessment,risk assessment,and zoning within the area,and provide basic basis for local disaster prevention and reduction management,geological hazard risk control,national spatial planning and use control,new rural areas,and key project planning and construction services.