Ecological Risk Assessment Of Geological Hazards In Global And “Three Parallel Rivers” Natural World Heritage Sites

The Natural World Heritage Sites has become the focus of the world because of its outstanding universal value in natural landscape,geoscience,biodiversity and other aspects.However,in recent years,frequent geological disasters have destroyed the structural and functional integrity of the ecological system of the heritage site,seriously threatening the sustainable development of the Natural World Heritage Site.Based on the principle of disaster geology and the theory of disaster risk assessment,taking geological disaster as the research object,taking vegetation as the disaster bearing body,using GIS and RS and other means,this paper analyzes the distribution and development characteristics and main dynamic mechanism of geological disaster,and carries out the geological disaster risk and ecology of the world natural heritage site from two scales of global and typical case("Three Parallel Rivers")Study on vulnerability and ecological risk assessment of geological disaster,so as to identify high risk and high ecological loss areas of geological disaster.Through the above research,this paper mainly draws the following conclusions:1.On the global scale,through the construction of the spatial relationship model between the Natural World Heritage Sites,geological disasters and vegetation,the quantitative evaluation of the risk and ecological vulnerability of three kinds of geological disasters,namely volcanic eruption,landslide and earthquake,has been realized.Based on the disaster risk evaluation model,the ecological risk of geological disasters in 239 world natural heritage sites has been classified.It is believed that 30(13%)of the world natural heritage sites have high ecological risk of geological disasters and are mainly distributed near the boundary of the earth plate and the earthquake fault zone.Crustal activity is the main driving force of various geological disasters caused by the Natural World Heritage Sites.2.Based on field investigation and data collection,this paper analyzes the environmental geological characteristics and development mechanism of geological disasters in the Natural Heritage Site of "Three Parallel Rivers".It is considered that the geological disasters in the study area are the product of the comprehensive effects of the earth's internal and external dynamics and human engineering activities.And the geological disasters in the study area have the characteristics of North-South strip distribution in space,mainly distributed in the transition zone of large geomorphic unit,fault zone and seismic zone,areas with strong river cutting and dense road network.3.Based on the 8 indexes of terrain slope,terrain relief,water system,rock and soil properties,fracture structure,rainfall,earthquake and human engineering activities,the information model of geological hazard risk assessment is established for the "Three Parallel Rivers" Natural Heritage Site;the NDVI value of vegetation is extracted based on Remote Sensing technology to realize the ecological vulnerability assessment of the study area.4.Based on the results of geological hazard risk assessment and ecological vulnerability assessment,based on the geological hazard ecological risk assessment model,it is considered that 34% of the Natural Heritage Site of "Three Parallel Rivers" have higher geological hazard ecological risk,and the high risk is mainly concentrated in the Nujiang River,Lancang River,Jinsha River and the river valley where their tributaries flow,while the low risk areas are mainly concentrated in the alpine mountain areas and the high-risk areas Town.