| On May 12, 2008 an earthquake broke out near Yingxiu town in Wenchuan county, directly caused the collapse of the mountain disasters such as landslide that is up to more than 60000. An earthquake caused the scale of geological hazard is rare. Outbreaks from the earthquake has in the past 6 years, and after the earthquake disaster area did not restore calm, collapse of the landslide in the environment under the action of heavy rainfall thereof resurrection, expand, or even into a source of solid loose materials added to the debris flow activities, destructive intensified. Collapse of landslide activities will continue for quite a long time, the scope of its activity and the risk has been evolving.This paper is mainly aimed at such problems as high wenchuan earthquake intensity area the subsequent evolution of landslide, analyzes the change and distribution characteristics of landslides from 2009 to 2013 in the study area through research on typical high earthquake intensity area near yingxiu, then in view of the landslide on the factors such as slope, aspect, elevation of distribution, researches main controlling factors of landslide distribution.Paper aims to study the landslide area of remote sensing dynamic change trend, reveal the landslide in geological environment fragile time and space distribution characteristics and laws of earthquake area, explore the main controlling factors in the landslide evolution through field investigation, further more high resolution of remote sensing image interpretation and theoretical analysis. So I can provide preliminary theoretical basis for complex mountainous geological disaster risk assessment and disaster prevention and mitigation. This paper get the following conclusion:1. Through the GIS platform, we interpret landslides on high precision of remote sensing images from 2009 to 2013, and get landslide area of remote sensing dynamic change trend. We also find the trend of landslide area overall decreased on time scales. Partition of monomer landslide area is reducing year by year as a whole, and partition of landslide sliding zone and sliding the area change rate is greater than the accumulation zone area of the rate of change; Landslide in the all 37 debris flow gullies decreases year by year from quantity to area; Regional landslides in the study area are mainly composed of small and medium-sized, and in reducing year by year : landslide area in 2011 than in 2009 decreased by 22%, decreased by 33% in 2013 than in 2011.2. By the GIS platform, the earthquake landslide spatial distribution on different time scales were analyzed, we find that landslide slope, aspect, elevation and other factors to the distribution characteristics in different years has a certain similarity. Under the elevation factor, 2009 landslides are mainly distributed in 1000-2000 m elevation, at the same time in 2011 and 2013 more than half of the landslide are mainly distributed in 1000-2500 m elevation; Under the slope factor, the distribution of landslide in different years is basically the same. Landslide more development on 30-50 ° slope, and basic and slope landslide distribution density were positively correlated to the size of the relationship: the greater the slope, the bigger the landslide distribution density. Landslide aspect to the factor of different years, mainly exist in the 120-200 ° slope to the range, and landslide area proportion and distribution density in each classification are basic to keep the shape of the normal distribution. Under the drainage distance factor, the landslide are mainly distributed in the range of 0-1000 m, and the proportion is as high as 90%. That is to say, the more significant the closer distance water system of landslide development.3. Comparative analysis landslide of the three periods of remote sensing image in slope, aspect, elevation of the six factors such as distribution and area of variation characteristics, preliminary obtained the research area for the basic controlling factor of landslide evolution phase image. Significant role is the lithology and the slope, aspect, elevation. Among them, the slope factor of landslide area changes in its control effect is 30 to 50 ° section, aspect control role to the factor of section is 120-200 °, elevation factor of landslide area changing most is the area at an altitude of 1000-2000 m, lithology factor of landslide changes the most obvious for diorite. In addition, rainfall,human activity and vegetation under certain conditions on the time and space distribution and evolution of landslide control effect. |
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