汶川震区陕西省宁强县滑坡灾害危险性分析与评价

在分析汶川震区陕西省宁强县滑坡灾害特征和危险性影响因素的基础上,利用开发的县域滑坡灾害风险管理GIS系统,选取斜坡坡度、地层岩性、地震动峰值加速度等8个因素进行滑坡灾害危险性分析。根据研究区13 477个网格单元信息量计算结果,将宁强县滑坡灾害危险性分为极高、高、中、低和极低5个危险等级。研究得出极高危险和高危险区主要集中在勉阳深大断裂带及其次级断裂区,约占研究区总面积的16%,滑坡点密度为20.5/100 km2.中等危险区分布于境内工程地质岩性较为软弱的区域,约占研究区总面积的42%,滑坡灾害点密度为6.3/100 km2.低危险区和极低危险区位于区内人口稀少的高远山区,约占研究区总面积的42%,滑坡灾害点密度为0.64/k100 m2.

Research on landslide hazard in Ningqiang county of Wenchuan earthquake affected area

On 12 May 2008, Wenehuan earthquake caused nearly a hundred of secondary geo-hazards in Ningqiang county, Shaanxi province. Based on the landslides risk investigation and geo-hazards spatial database analysis, the factors of slope angle, slope aspect, slope elevation, fault structure, formation li- thology, rainfall, peak acceleration of ground motion, and engineering activity were selected for land- slides hazard assessment. The information model was then applied to calculate landslides hazard by u- sing County Landslide Risk Management Information System （CLRMIS, developed by authors）. All of the 13 477 units sized 500 m×500 m were calculated and analyzed. Finally, the landslides hazard was divided into five classes, i.e. extremely high, high, moderate, low and extremely low. The area with extremely high and high hazard mainly lies in the MIAN-YANG deep fault and its secondary faults zone, accounts for 16% of the study area, and the landslides density is 20.5/100 km^2. The moderate hazard accounts for 42% of the study area, the landslides density is 6.3 km^2 and mainly in the weak strata region. The low and extremely low hazard area in the sparsely populated region, accounts for 42% of the study area, and the landslides density is 0.64/100 km^2.