Investigation and landslide risk zoning in Nirchai basin using ANP model

Landslide is one of the most important geomorphological processes of slopes, which in addition to its significant role in the evolution of slopes, is sometimes considered as a serious hazard. In this regard, the preparation of landslide risk zoning maps is one of the basic strategies to reduce the risks of this phenomenon. In the present study, the risk of landslides in the Nirchai catchment area, located in Ardabil province, was evaluated. The research methodology is based on the Network Analysis Process (ANP) model in the context of GIS. For this purpose, 10 variables affecting the occurrence of landslides including the variables of slope, slope direction, height, slope length, convexity of the surface, geological formations, precipitation, distance from waterway, vegetation and land use were included in the model. The results show that the three variables of slope (weight 0.217), lithology (weight 0.217) and precipitation (weight 0.167) are the most important and, in fact, the main controllers Landslide processes at the surface of Nirchai catchment area are considered. The results of landslide risk zoning also indicate that about 9.8% of the surface of Nirchai basin is in the high risk class and about 19.3% of it is in the high risk class. High-risk and high-risk areas are mainly scattered in the middle parts of Nirchai basin. In this part of the basin, various variables such as suitable slope (especially 20 to 40%), vulnerable geological formations, average altitude, receiving favorable rainfall, high drainage density, etc. have increased the potential for landslides.