A Study On Landslides In Wenchuan Earthquake And Their Influencing Factors

The Neotectonics is strong, and active tectonics develop very much in China, where is the region that mainland earthquake is the most concentrated and t activity in the world. The earthquake landslides are the most disastrous consequence of earthquake shaking, regarded as one of the main secondary disaster in mountainous area, which can cause great loss and casualties to exacerbate the destructive impact of earthquake greatly. In West China, the change of geological environment and the landform is very sharp; surface is fragmented under water erosion and strong weathering, so that strong earthquakes always trigger numerous landslides. Therefore, it is helpful to research the correlation between earthquake landslides and influencing factors for the disaster appraisal and the earthquake landslide prevention.The earthquake landslides’ distribution is not only related to earthquake intensity and spread of fault rapture, but also to terrain etc. Understanding the relationship between earthquake landslides and influencing factor is important for disaster evaluation. By interpreting medium and huge landslides from remote sensing images which cover more than30000km2of Ⅶ—Ⅺ seismic intensity area of Wenchuan earthquake, GIS layers are constructed to reflect earthquake intensity, the spread of cracked faults, terrain conditions etc to analyze the relationship between earthquake landslides`distribution and influencing factors. Try to build landslides hazard analysis model using a GIS approach used for research area. It is found that BP neural networks are more applied to predict the earthquake landslides, which produces acceptable results as well by comparative analysis of each mold in results and actual situation. The main findings are as follows:1. The landslides mainly distributed in the place near to the cracked faults, however, the attenuation speed is different in the two direction that perpendicular and parallel to the cracked faults, what is more, which in perpendicular’s direction is faster than parallel’s2. The earthquake landslides happened mainly in1.0km to1.5km in elevation and concentrated in25°～40°slope angle. 3. The relationship between aspect and the fault direction decide the landslides density, the study show that where the aspect point to epicenter or in perpendicular to fault split direction is high density. The earthquake landslides happened manly in aspect of east, southeast and south as well, about half of the whole.4. The local relief has obvious control action on landslides, landslides mainly happened in middle slop, and up slope and down slope are the secondary.5. The model build by the most approach method applied to Wenchuan earthquake landslides to realize landslide hazard analysis of landslide research area. The results are in agreement with actual situation.6. The linear model based on least square is simple and available, the application of which is meaningful in earthquake landslide disaster’s preliminary fast evaluation.7. The BP neural networks are non-linear model dose well in fitting the relationship between earthquake landslides and influence factor, and has high recognition rate to the landslides.