Study On Evaluation Of Landslide Susceptibility In The Middle Reaches Of Bailongjiang Basin

Geological disasters occur frequently in our country,which have been seriously affected people's living environment and the development of the national economy.Landslide is the most important type of disaster.The occurrence of landslide disaster has obvious clustering.However,many existing related studies mainly focus on large-scale single landslides,and lack of research on regional landslides.An important prerequisite for researching regional disasters is to evaluate the vulnerability of disasters and map the results on a map to achieve effective regulation of disasters.At present,most of the landslide susceptibility evaluation is based on historical landslide data,which is known to predict unknown.Nevertheless,insufficient or poor real-time data of historical landslide will lead to deviation of evaluation results.Time-series InSAR technology has great advantages in monitoring small surface deformations.For the middle reaches of the Bailong River where large landslides gather,this paper discussed the feasibility of landslide susceptibility evaluation based on landslide deformation points extracted by SBAS-InSAR technology and Sentinel-1A image as data source.The results of the evaluation and the classification of the easy-to-issue grades were used to explore the regional differences of the landslides in the middle reaches of the Bailong River.The main results and conclusions were as follows:(1)According to whether the radar beam can be irradiated to the surface,the study area was divided into low sensitive area,visible area and invisible area.The historical landslide data and the visibility results were superimposed,and the results showed that the used SAR images were suitable for the needs of this study.(2)This study obtained 103432 deformation points by using SBAS technology.According to the conditions of landslide development and the movement rate,63378 landslide deformation points were screened out.The reliability analysis by using nuclear density analysis and historical landslide data.It showed that the landslide deformation point after screening has good consistency with historical landslide data.(3)According to the formation mechanism of the landslide,7 factors were selected according to the existing research and the actual situation of the study area,and the relationship between each factor and the landslide development was analyzed by qualitative and quantitative analysis.The results showed that the order of influence of various factors in the study area on landslide development is:distance from water system>formation lithology and rock group>distance from fault>slope>slope direction>undulation>elevation(4)Based on the grid unit and the slope unit,the evaluation model has been constructed by the information method,and the evaluation results are verified by historical landslide data and field verification.On this basis,the degree of landslide susceptibility is graded.The area of the high-incidence area of the landslide in the study area accounts for 33.06%of the total area,covering 85.77%of the landslide deformation points and 76.67%of the historical landslide points.And they were mainly distributed in areas where the lithology of the formation is medium-thick slate,glutenite,medium-thin fine sandstone,siltstone,thin-layer limestone and faults.The results showed that using the landslide points extracted by SBAS technology for landslide susceptibility evaluation is feasible and effective.And it should be necessarily pay attention to the high-incidence areas of landslides for urban construction and water conservancy projects in the future.