Multi Scale Analysis And Evaluation Of Landslide Geological Disaster Based On RS And GIS

Landslide is a worldwide disaster phenomenon, and is very sudden and devastating. The natural conditions and geological environment of Luding determine the necessity of a landslide occurrence. Select Luding as the object, through analysis the development and distribution of landslide in the study area to establish the different scale evaluation index system, then using analytic hierarchy process and Liu Xilin model to do watershed scale hazard evaluation and single channel scale hazard evaluation. Finally, through investigation and verification,research and analysis of landslide from different scalses. The main results are as follows:(1)Landslide hazard evaluation can be divided into watershed scale hazard evaluation and single channel scale hazard evaluation. Selecting the basin range of Luding country and Chesuo Channel as the object to complete watershed scale hazard evaluation and single channel scale hazard evaluation. For regional landslide hazard evaluation, using GIS and RS to finish remote sensing interpretation, and then through investigation and verification to confirm the distribution of landslide in the study area. In the stydy, the DEM as the main data source, using hydrological analysis module of ArcGIS to extract watershed unit. Research shows, when the water catchment threshold is 10000, the basin extracted is ideal, and the study area is divided into 185 basins.(2)Watershed scale system includes 8 indicators like the channel density, lithology, precipitation, slope and distance from the structure, and distance from the road, elevation, NDVI. Using AHP analysis to do hazard evaluation on watershed scale of Luding County, the evaluation results can be divided into five grades, which represent very high hazard area, high hazard area, medium hazard area, low hazard area and very low hazard area. The evaluation results show that high and very high hazard area are mainly distributed in the main stream of Dadu River, Luding fracture, Moxi fracture, and both sides of Detuo fracture. Moreover, the hazard partition results of landslide conform to the feature that the smaller of the distribution density of landslide, the lower the hazard level, and the larger of the distribution density of landslide, the higher the hazard lever. Therefore, using AHP analysis to do hazard evaluation, the results has a certain credibility.(3)As for single channel landslide, using Liu Xilin evaluation model to do quantitative evaluation of Chesuo channel landslide. Firstly, use ZY-3 satellite image stereo resources to generate high precision DEM data of Chesuo Channel, then the DEM data was used as the one after the outbreak of landslide. Secondly, use the 30 m DEM in 2004 as the one before outbreak of landslide. Using the two DEM datas and Fill tool of ArcGIS to calculate the solid amount out of landslide, then get the solid amount out of landslide is 319000m3. Next, evaluate other index of the Chesuo Channel: outbreak frequency(2.38 times/100 years), and basin area(18.64km2), and main ditch length(8.21km), and basin relative height(2100m), and basin cutting density(1.63km-1), and unstable ditch bed proportion(270%), Then apply Liu Xilin appraisal of hazard degree model to finish hazard degree evaluation. Results showed that Chesuo Channel is moderately hazardous landslide. Subsequently, utilize Liu Xilin vulnerability degree evaluation model to finish vulnerability degree evaluation. According to material and economics to calculate vulnerability degree, the results showed that the Chesuo channel is a high vulnerability degree landslide. Finally, according to Liu Xilin risk evaluation model "hazard ? vulnerability = risk", it proves Chesuo channel is a moderately hazard, highly vulnerable, and high risk landslide.In this paper, Landslide is evaluated from watershed scale and single channel scale. When doing the research, different scale have different emphasis. The evaluation results have different uses. The watershed scale evaluation results reflect the overall characteristics and spatial heterogeneity of landslide, which can provide basis for prevention measures, regional planning and macro decisions. The single channel scale evaluation is focused on the scale and of landslide and the degree of the loss, the results can provide more practical theoretical basis for prevention work and prediction.