Abstract:

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 snowmelt 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 controlling factors for the development of debris flows.

Key words: geohazards, distribution characteristics, main controlling factors, frequency ratio, receiver operating characteristic curve, Ili Valley