基于GIS的四川省降水诱发型滑坡泥石流风险区划

GIS-based Zoning of Rainfall-induced Landslide and Debris Flow Risk in Sichuan Province

通过分析四川省滑坡泥石流地质灾害的致灾因子危险性、孕灾环境敏感性和承灾体脆弱性,构建了四川省降水诱发型滑坡泥石流风险评估指标体系,并基于灾害系统学原理的风险评估模型,结合层次分析法和信息量法,利用GIS工具完成了四川省降水诱发型滑坡泥石流地质灾害风险区划。结果表明:(1)诱发滑坡泥石流前期15 d平均有效雨量较大的区域主要位于四川盆地北部、西南部、东南部分地区和攀西地区南部,较小的地区主要位于川西高原和盆地中部。(2)四川盆地北部、西南部和攀西地区东部是降水致灾因子危险性等级最高区域,盆周山区、攀西地区以及阿坝州东部地区孕灾环境敏感性等级在较高及以上,中等以上承灾体脆弱性等级基本位于盆地地区,盆周山区、川西高原及攀西地区脆弱性等级大多在中等以下。(3)风险区划显示高危险区主要分布在盆地北部、西南部和攀西地区,与四川省滑坡泥石流活动情况一致。

By analyzing the disaster-causing factors,disaster-generating environment and the vulnerability of disaster-bearing body,the risk assessment index system of rainfall-induced landslide and debris flow geological disaster in Sichuan province was constructed.Based on the risk assessment model of disaster systematic theory,the risk regionalization map of rainfall-induced landslide geological disaster in Sichuan province was finally obtained by using AHP and information value method with the help of GIS tools.The main results are concluded as follows:(1)The areas with large average effective rainfall in the early 15d of landslide debris flow were mainly located in north,southwest,southeast of Sichuan Basin and southern Panxi region.The smaller areas were mainly located in the western Sichuan plateau and central Basin.(2)The north,southwest of Sichuan Basin and eastern Panxi region were the regions with the highest risk level of rainfall disaster-causing factors.The level of environmental sensitivity to natural disasters in the mountainous areas surrounding the Basin,the region of Panxi and the eastern part of Aba prefecture was above the higher level.The vulnerability level above medium of disaster-bearing bodies was basically located in the Basin area.Most of the vulnerability levels in the mountain areas surrounding the Basin,the western Sichuan Plateau and the Panxi region were below the medium level.(3)The results of risk regionalization showed that the highrisk areas were mainly distributed in northwest,northeast and southwest of Sichuan,which was consistent with the actual landslide and debris flow activities in Sichuan province.