南充市滑坡灾害易发性区划与评价

Risk Zonation and Evaluation of Landslide Geohazards in Nanchong

选用高程、坡度、降水量、河流影响距、道路影响距、人口密度分布、归一化植被指数、岩性、土壤类型和土地利用类型作为南充市滑坡灾害易发性区划评价因子,并结合85%的历史滑坡灾害数据,采用确定性系数模型对评价因子进行量化和权重确定;构建二元逻辑回归模型对评价因子的贡献度进行评价以及对南充市潜在滑坡灾害发生概率进行空间预测;逻辑回归分析结果表明,土地利用类型、6-9月降水量、归一化植被指数、土壤类型、岩性、道路影响距、人口密度分布和坡度是南充市滑坡灾害的主要影响因素,其中,6-9月降水量对滑坡灾害易发性概率值影响最大,其次为土地利用类型,再次为坡度,归一化植被指数评价因子对滑坡灾害易发性概率值影响最小;根据南充市潜在滑坡灾害发生概率值大小,采用自然断点法,将南充市滑坡灾害分为低滑坡灾害易发区、较低滑坡易发区、中滑坡易发区、较高滑坡易发区和高滑坡易发区,区划结果表明,南充市滑坡灾害高易发区分布于仪陇县全境、营山县东部、蓬安县东南部、阆中市东北部地区和顺庆区南部地区;利用15%的历史滑坡灾害数据对区划结果进行验证,验证数据与南充市易发性区划结果吻合度较高,说明南充市滑坡易发性区划结果可信。

We choose elevation,slope,precipitation,river influence distance,the road distance,distribution of population density,normalized vegetation index,lithology,soil types and land use type as Nanchong landslide disaster prone probability evaluation factor,combined with the 85%of historic landslide disaster data,by using the deterministic coefficient model to quantify the evaluation factors and determine the weight;We construct a binary logistic regression model to evaluate the contribution degree of the evaluation factors and made a spatial prediction of the occurrence probability of potential landslide in Nanchong city.Logistic regression analysis results showed that the land use type,precipitation from June to September,normalized vegetation index,soil type,lithology,road influence distance,the population density distribution and the slope are the main influence factors of landslide disasters in Nanchong,among them,precipitation from June to September has a largest impact on the prone probability value of landslide hazards,followed by land use type,again for slope,normalized vegetation index evaluation factors have an minimal influence on the prone probability value of landslide hazards;According to the probability of occurrence of potential landslide hazards in Nanchong city,the natural breakpoint method was used to divide the landslide hazards in Nanchong city into lowest-landslide hazard prone zones,low-landslide hazard prone zones,middle-landslide hazard prone zones,high-landslide hazard prone zones and highest-landslide hazard prone zones,regionalization results showed that the landslide hazard prone areas in nanchong city are distributed in the whole area of Yilong county,the east of Yingshan county,the southeast of Pengan county,the northeast of Langzhong city and the south of Shunqing district;The results were verified by using 15%of the historical landslide disaster data,and the results were in good agreement with the results of the prone landslide zoning in nanchong city,indicating that the results of the prone landslide zoning in nanchong city were reliable.