汶川地震极重灾区地形起伏度特征及其与生态环境受损关联分析

采用DEM数据对汶川地震极重灾区地形起伏度特征分析，海拔高度和地形起伏度总体上是南西高，北东低。5km×5km单元地形起伏度〉1000m的区域面积占27．98％。0．5km×0．5km单元〉100m的区域面积占50．63％。在8．0级主震和6．4级余震震中之间典型区段剖面0．5km间隔分析中，南西段起伏度大于北东段，南西段起伏度〉200m区段占全段14．84％，北东段仅占6．64％。地震导致生态环境受损程度的差异与地形起伏度的差异在空间分布上有一定的重合，具有高起伏度的南西段生态系统破坏面积占总破坏面积的88．55％，新增水土流失面积占新增总面积的70．99％。地震灾区地形起伏度是生态环境遭受严重破坏致灾关联因素之一。

The Characters of Relief Amplitude in the Severest Disaster Area of Wenchuan Earthquake and Its Association Analysis with the Eco-environmental Damage

The DEM data were adopted to conduct a feature analysis of relief amplitude for the severest disaster areas of Wenchuan earthquake. The results showed that as a whole the southwest was higher than northeast. The percentage of the area accounted for 27. 98% and 50. 63% at where the relief amplitude of5km ×5km square 〉 1000 m and 0. 5km ×0. 5kin square 〉 100 m, respectively. The cross section analysis with intervals of 0. 5 km in the typical region between the epicentrums of principal earthquake with Mw 8. 0 and aftershock with Mw 6. 4 showed that the relief amplitude in the southwest was higher than northeast. The area where the relief amplitude was more than 200 m accounted for 14. 84% in southwest compared with 6. 64% in northeast. There were some coincidences between the damage degree of eco-environment caused by earthquake and the relief amplitude in the area. Actually the area with severely damaged eco-system in the southwest, where the relief amplitude was high, accounted for 88.55% of the total of damaged area, and 70. 99% for newly increased area of soil erosion. The relief amplitude should be one of the associated factors leading to the heavy damage of eco-environment.