基于ASTER GDEM的地形起伏度与西安市长安区滑坡崩塌灾害的相关性

西安市长安区地势南高北低,相差悬殊,秦岭北坡和黄土台塬边坡因人类工程活动、降雨、地震等诱发的影响,容易发生滑坡崩塌地质灾害,给城市造成严重损失。为研究滑坡崩塌地质灾害发育与地形起伏度的关系,以空间分辨率为30 m×30 m的ASTER GDEM数字高程数据为数据源,基于GIS的邻域统计分析工具,依次提取2×2、3×3、4×4、5×5……50×50共49个矩形窗口,运用均值变点法科学地确定长安区地形起伏度最佳分析窗口大小为17×17,面积为26.01×10^(4)m^(2),据此将区内地形起伏度分为5级,并采用CF法、I值法建立区域地形地貌与灾害点分布之间的相关关系。研究表明,滑坡崩塌的发育与地形起伏度具有密切的相关性,地形起伏度为小起伏(30~200m)时,对滑坡崩塌灾害影响最大,最利于灾害的发育。

The terrain of Chang'an District in Xi'an City is high in the south and low in the north,and the northern slopes of the Qinling Mountains and the edges of the loess plateau are prone to landslide avalanche geologic hazards due to the induced impacts of human engineering activities,rainfall,and earthquakes,which cause damage to the city.In order to study the relationship between the development of landslide avalanche geohazards and the degree of topographic relief,the ASTER GDEM digital elevation data with a spatial resolution of 30 m×30 m was used as the data source,and based on the neighborhood statistical analysis tool of GIS,a total of 49 rectangular windows of 2×2,3×3,4×4,5×5,...,50×50 were extracted in turn,and the mean change-point method was applied to scientifically determine the best analysis window size of Chang'an District topographic relief is 17×17,the area is 26.01×10^(4)m^(2),according to which the topographic relief in the district is divided into 5 levels,and CF method and I-value method are used to establish the correlation relationship between regional topographic relief and the distribution of disaster points.The study shows that there is a close correlation between the development of landslide avalanches and the degree of topographic relief,and when the degree of topographic relief is small relief(30~200 m),it has the greatest influence on the landslide avalanche disaster,and is most favorable to the development of the disaster.