【摘要】 采用DEM数据对汶川地震严重灾区(11个县市)海拔高程和地形起伏度分布特点分析,海拔高度和地形起伏度总体上是西南高,东北低。海拔1500m以上区域面积占55.34%,其中海拔3000m以上区占19.67%。5km×5km单元地形起伏度>1000m的区域面积占23.92%。1km×1km单元地形起伏度>200m的区域面积占44.78%。灾区核心地段剖面海拔650～3500m,800～2000m地段占全线段73.74%。对剖面线1km单元段起伏度分析结果表明,南段起伏度大于北段,南段>300m地段占39.07%,北段>300m地段占17.97%。地震导致生态环境受损严重的地方主要分布在西南部。西南部既是地震震中区域,又是高海拔-高起伏度区域,有一定的重合。西南部区域生态系统破坏面积占总破坏面积的87.25%,新增水土流失面积占新增总面积的68.06%。汶川地震灾区生态环境遭受严重破坏因果关系链是:强烈地震+断层效应+地形因素等→地质灾害→植被和生态系统受损→生态功能受损。更多还原

【Abstract】 Based on the DEM data, the relief amplitudes of the severest disaster areas of Wenchuan earthquake(including 11 counties) are analyzed.The results show that the southwest is higher than northeast in the area.The regions where the elevation is more than 1 500 m account for 55.34% of the total area, and those with the elevation of more than 3 000 m account for 19.67% .The regions where the elevation is less than 800 m are mainly in the south, and account for 18.59%.The acreage of the region where the relief amplitude within 5 km×5 km grid size is greater than 1 000 m accounts for 23.92% .The acreage of the region where the reliefamplitude within 1 km ×1 km grid size is greater than 200 m accounts for 44.78% .The elevation of the core disaster area(between the epicentrums of Mw8.0 earthquake and Mw6.4 aftershock) ranges between 650 m and 3500 m.And among this area, the regions where elevation is more than 800 m and less than 2 000 m account for 73.34% of the area.The regions with high elevation and relief amplitude are mainly in the west of the area.The results of analyzing the relief amplitude within 1 km grid size show that the relief amplitude in the south is higher than in the north, and the regions where the elevation is more than 300 m account for 39.07% in the south area and 17.97% in the north area, respectively.The regions where the eco-environment is seriously damaged by the earthquake are mainly in the southwest.The southwest is the center of the earthquake and is also the region with high elevation and relief amplitude, which indicates that there may be some relationship between the damage degree of eco-environment caused by earthquake and the relief amplitude in the area.The acreage of damaged eco-system in the southwest where the relief amplitude is higher accounts for 87.25% of the area, and the acreage of new soil erosion accounts for 68.06%.The chain of causation of the seriously damaged eco-environment in the disaster areas could be described as:strong earthquake + fault slipping + topography →Geological disasters →damaged vegetation and eco-system→damaged ecological functions.更多还原