Landslide Susceptibility Assessment Based On ArcGIS In Yanchang County

Landslide is one of the major geological disasters in China,seriously restricting the development of the national economy.Yanchang County is located in the eastern part of Yan'an City,Shaanxi Province,is situated in the northern of Shaanxi Loess Plateau,the county is almost covered by different thickness of the loess,belonging to the typical loess plateau landscape.In the study area,there are many hills and gully,the geological environment is fragile,geological disasters often occur,especially the loess landslide.Yanchang County is one of the geological disasters prone area in Shaanxi Province.According to field investigation and study,there were 83 landslide disasters in the study area,including 45 small landslides,37 medium-sized landslides and 1 large landslide.Although there was no large-scale and giant landslide,the landslides pose a serious threat to people's lives and property.It is an important measure to carry out susceptibility assessment of landslide disaster in order to prevent and mitigate the loss caused by landslide hazard.The main research work and achievements are as follows:(1)Based on ArcGIS software,first,we integrate the relevant data of the study area,second,the statistical analysis method is used to determine the importance of various influencing factors to the historical landslides.Finally,the susceptibility evaluation factors we select are lithology,slope,slope height,aspect,geomorphology and loess thickness,and then taking the landslide density value as the index to realize the factorization quantization.(2)The analytic hierarchy process(AHP)is used to evaluate the landslide susceptibility,and in this part,we choose slope unit and the grid unit as the evaluation unit respectively.After compare the landslide susceptibility zoning map and the historical landslides distribution map,it is find that the evaluation result based on the slope unit is more reliable than the grid unit,which indicates that the slope unit is more suitable for the evaluation of the landslide susceptibility in the research district.(3)The logistic regression model and the BP neural network model are applied to evaluate the susceptibility respectively,based on the slope unit.Compared with the results of the AHP,the overall trend of the evaluation results of the three evaluation models is consistent.In contrast,BP neural network model has the highest reliability,followed by AHP,and the logic regression model's is relatively low.(4)Through the analysis of landslide susceptibility zoning map,we find that the high-prone areas in the study area are mainly concentrated in the small part of the north of the county,western part of the Yanhe River and its tributaries.The low-prone areas are mainly located in the eastern region and the central part of the county which is far away from the river trunk.