GIS支持下川滇黔接壤区滑坡危险性评价

川滇黔接壤地区是中国滑坡灾害的多发区,区内共有崩塌、滑坡等地质灾害隐患点1.2万余处,对100余万人的生命与财产安全构成威胁,严重影响当地人民生产、生活安全与可持续发展。选择坡度、相对高差、到活动断裂带距离、年均降雨量和年均大雨日数5个因子作为滑坡危险性的评价因子,在GIS支持下获取各因子的贡献权重,根据贡献率模型在空间叠加下生成研究区滑坡危险性评价图。结果表明:(1)研究区1.92×105 km2面积中,极高危险区3.92×104 km2,高危险区4.34×104 km2,中危险区4.58×104 km2,低危险区3.92×104 km2,稳定区2.42×104 km2,中度以上危险区面积占研究区总面积的67.00%;(2)极高危险区主要分布在小江—安宁河深大断裂两侧以及金沙江、雅砻江等深切河谷中,显示出活动断裂带和地貌对滑坡危险性的宏观控制作用;(3)中度以上危险区内人口总量约1 152.31万人,占总人口的32.17%;GDP约419.88亿元,占研究区总量的28.75%,因此加强川滇黔接壤地区地质灾害防灾减灾能力建设已刻不容缓。

Evaluation of Landslide Hazards in Border Areas of Sichuan,Yunnan and Guizhou Province Based on GIS

The border areas of Sichuan,Yunnan and Guizhou Province are greatly hit by landslides.There are 1.2 million hidden dangerous points experiencing geological disasters,which have threaten more than 100 million lives and property security,and have negative effects on production,livelihood security of local people and sustainable development.The five evaluation factors of gradient,relative height distance to active fractures,annual average rainfall and annual average number of heavy rain days are selected to calculate their contribution weights.With the support of GIS,the map for landslide hazard evaluation in the area is drawn by using superposition method and the contribution rate model.Results show that:(1) The study area(about 19.18×104 km2) contains very highly dangerous zone(3.92×104 km2),highly dangerous zone(4.34×104 km2),moderately dangerous zone(4.58×104 km2),slightly dangerous zone(3.92×104 km2) and stable zone(2.42×104 km2).The areas of very highly,highly and moderately dangerous zones account for 67.00% of the total area.(2) Very highly dangerous zone is mainly located in the two sides of deep fractures in Xiaojiang—Anning River and deep valleys of Jinsha River and Yalong River,which implies that active fractures and landform play a macro-control effect on landslides.(3) The population in very highly and highly dangerous zones is about 11.5231 million,accounting for 32.17% of the total,and GDP is about 41.988 billion yuan,accounting for 28.75% of the total.So,it is essential to strengthen the capacity of preventing and reducing the geological hazards in the area.