Risk Assessment Of Geological Hazards In The Central Area Of Nyingchi Based On Remote Sensing And GIS

The central part of Nyingchi is located in the southeastern part of Tibet.It is a strong intersection of mountainous structures and different geological tectonic areas.It is affected by geological and tectonic effects.The natural conditions such as topography,climate,and hydrology are extremely complex.Geological disasters are widely distributed and diverse.It is a huge hazard and has caused serious threats to the construction of the project.The construction of the project will inevitably cause disturbance to the environment.Human engineering activities such as excavation and blasting will inevitably impact the sensitive and fragile plateau ecological geological environment,destroying the original balance and causing geological disasters.In order to deepen the understanding of the geological disasters(collapse,landslide and debris flow)in the central area of Nyingchi and the actual needs of disaster prediction and prevention,this paper takes three districts(counties)of Nyingchi County,Bomi County and Mainling County as research objects.Through the investigation of the geological disasters in the region and the collection of related data,based on remote sensing and GIS technology,the development characteristics and distribution of geological disasters are quantitatively revealed.The analytic hierarchy process and the weighted information model are used to analyze the geological hazard risk assessment and its regional differentiation law.Based on the results of risk assessment in the central area of Nyingchi,put forward reasonable suggestions for prevention and control of geological disastersThe main results are as follows:? Analyze and compare remote sensing interpretation methods and operational procedures,complete the interpretation of historical disasters in the study area,making 3D remote sensing image maps,and analyze the spatial distribution of historical geological disasters.The development level map of disaster points(collapse,landslide,debris flow)in the study area is formed.The high development area of geological disasters accounts for 18.75% of the total area,and the development area of geological disasters accounts for 33.37% of the total area.? Under the condition of fully understanding the disaster background of the study area,the risk factors evaluation system is constructed by three parts: Foundation Factors,Induction Factors,Disaster History Factors.The analytic hierarchy process and the weighted information method were used to calculate the evaluation results.The study area was divided into four levels: extremely high risk zone,high risk zone,moderate danger zone and low risk zone,and the area statistics were respectively carried out.? The area of high-risk area of geological disasters in the study area is 9272km2,which is 27.44% of the total area.The area of extremely high-risk area is 3691km2,which is 10.92% of the total area.It is mainly distributed in Parlung Zangbo,Yigong Zangbu,Nyang Qu.The area around the middle and lower reaches of the Yarlung Zangbo and the G318 National Road and the S306 Provincial Road are affected by human engineering activities.The results of township geological disaster risk assessment are analyzed,and the key prevention areas and low-incidence areas of geological disasters are divided.? For the impact of grid engineering planning,construction and operation phases and geological hazard hazards,construct the Thiessen polygon,perform area statistics on the risk classification index of the segment polygon,and establish the division method to further analyze the geological disaster risk impact in the region.According to the classification of engineering routes in the study area,the construction of different grades of engineering sections is proposed.