甘肃省积石山县泥石流空间分布及分析

Spatial distribution and analysis of debris flow in Jishishan county of Gansu province

泥石流灾害突发性强,成灾速度快,危害严重,易给人民生命财产和社会基础建设造成严重损失。本文以甘肃省积石山县2018年8月2—3日泥石流发生时的降雨数据为临界值,结合该地区地形地貌、土壤土质、植被覆盖、水文等环境变量数据,利用GIS技术进行数据分析,发现积石山县刘集乡、石塬乡、大河家镇等为泥石流灾害高危易发区域。引发当地泥石流的原因主要为:①植被破坏严重,土体不稳定,强降雨引起泥石流;②研究区属于黄土高原地貌,水体侵蚀导致极易发生泥石流;③对黄河沿岸破坏较为严重,夏秋汛期,黄河水量猛增,对没有植被保护的土壤剧烈冲刷,为泥石流的发生提供了物质条件。

Debris flow disasters are sudden,rapid and serious,easy to cause serious losses to people's lives,property and social infrastructure construction.Taking the rainfall data when mudslide occurred in Jishishan county from August 2 to 3,2018 as the critical value,combined with the data of environmental variables such as terrain and geomorphology,soil quality,vegetation coverage and hydrology in the region,it is found that the areas such as Liuji township,Shiyuan township and Dahejia township of Jishishan county are prone to high risk areas of debris flow disasters through data analysis with GIS technology.There are three main causes of local mudslides.①The local vegetation is seriously damaged so that the soil is unstable and heavy rainfall easily causes debris flow.②The research area belongs to the Loess Plateau landform,and debris flow is easy to occur under the erosion of water.③The damage along the Yellow River is more serious.In the flood season of summer and autumn,the water volume of the Yellow River increases sharply,and the soil without vegetation protection is severely eroded,providing material conditions for the occurrence of debris flow.