伊犁谷地地质灾害分布特征及主控因素分析

Distribution characteristics and main controlling factors of geohazards in Ili Valley

伊犁谷地滑坡、崩塌、泥石流、地面塌陷等地质灾害频发,灾害形成的影响因素多样。基于伊犁谷地地质灾害数据库,利用频率比法、接受者操作特征曲线(Receiver operating characteristic curve,ROC)等统计分析方法,研究伊犁谷地地质灾害的分布特征,分析地质灾害发育的主控因素。结果表明:(1)伊犁谷地地质灾害整体发育程度东部大于西部,集中在500~3500 m高程的中低山区。在时间上,主要集中在春夏融雪和降雨季节。(2)地质灾害的发育受地层岩性、地质构造、地形地貌、降水等多因素影响,但不同类型地质灾害的主控因素不同,滑坡受地层岩性、高程、坡度、年降水量的影响最明显,崩塌主要为坡度、高程、距断层距离因素控制;地面塌陷明显受高程、距断层距离、降水量的影响,基本由地下采矿活动诱发;距断层距离和高程是泥石流发育的主控因素。

Geohazards such as landslides,rock fall,debris flow,and ground collapse occur frequently in the Ili Valley,Xinjiang,China,and there are various influencing factors for the formation of these geohazards.Based on the database of geohazards in the Ili Valley,this paper uses statistical analysis methods such as the frequency ratio and receiver operating characteristic curve to study the distribution characteristics and main controlling factors of geohazards in the Ili Valley.The results show the following:(1)The overall development degree of geohazards in the Ili Valley is greater in the east than in the west,and they are distributed in the middle and low mountains with 500-3500-m elevation.In terms of time of occurrence,they are mainly clustered in the spring and summer snow-melt and rainfall seasons.(2)The development of geohazards is affected by stratigraphic lithology,geological structure,topography and geomorphology,precipitation,and other factors.However,the main controlling factors for different types of geohazards are different.Landslides are most obviously affected by stratigraphic lithology,elevation,slope,and annual precipitation,while rock falls are mainly controlled by slope,elevation,and distance from faults.Ground collapses are obviously affected by elevation,distance from fault,and precipitation,and are basically induced by underground mining activities.The distance and elevation from faults are the main control-ling factors for the development of debris flows.