基于模糊综合评判的汶川8.0级地震重灾区滑坡泥石流气候风险评估

用1971-2000年的30年逐日降水量资料,按旬统计汶川地震重灾县5-12月各旬的雨日、中雨日、大雨日、暴雨日的平均日数和气候概率,根据地震重灾区实际地质环境条件,降低强降雨强度条件,基于模糊综合评判法,按照最大隶属度原则对汶川特大地震重灾区的39个县进行地质灾害时空气候风险评估。结果表明:重灾区的地质灾害气候风险指数值存在两个高值期间,一个是5月中旬至7月上旬,另一个是8月下旬至9月下旬。而10月下旬至次年4月,重灾区降雨明显减少,绝大部分地区没有地质灾害气候风险;从地域分布来看,高风险区域主要集中在重灾区的西部和中部,风险等级为3～4级(风险较大或很大),东部地区风险等级为1～2级(中等风险或风险较小),但7月下旬高等级风险区位置集中在重灾区的南部和东部。

Risk Assessment of Landslide and Debris Flow in Main Disaster Area of Wenchuan Earthquake based on Fuzzy Integrated Evaluation

Based on 30 years’ daily precipitation data from 1971 to 2000,the authors statistically calculated the average number of days and climate probability of rain,moderate rain,heavy rain,and rainstorm in 10 days from May to December.Since the condition of Geological environment is poor in the main disaster area,we have lessened strength condition of strong rainfall.Then in virtue of Fuzzy Integrated Evaluation,we have done spatio-temporal and climatic rick assessment of geological hazard on 39 counties in the main disaster area of Wenchuan area,based on maximum membership principle.The results show that there are the two high climatic risk index values in main disaster area,one is from mid-May to early July,and another is from late August to late September.In addition,from late October to April of the next year,rainfall declined seriously in main disaster area,of which most part did not have climatic disaster.In terms of geographical distribution,high-risk areas are mainly concentrated in the west and central of main disaster area,where the risk level is 3～4(high risk or great risk);well,the risk level of eastern part is 1～2(moderate risk or little risk).However,in late July high-risk area focused on southern and eastern part.