Risk Assessment Of Landslide Disaster In Wenzhou Based On ArcGIS

Wenzhou is located in southeast coast of our country, between annual June and September, heavy rains brought by the typhoon easily leads to collapse, landslide, mud-rocks flow and other geological disasters occurred, which cause serious casualties and property losses, and constraint the local economic development in some certain. Therefore, in order to reduct the losses caused by geological disasters, risk assessment of geological disaster should be processed as soon as possible in the region.This research is based on ArcGIS technology, on the basis of comprehensive statistical analysis of survey data of Wenzhou city landslide disasters, and considering the old risk assessment model, the paper established a risk assessment formula,'Risk=Hazard×Vulnerability/Disaster prevention and reduction'while townships are choiced as the basic units of evaluation. Under this formula, at first, vulnerability assessment model is established by fuzzy comprehensive evaluation theory and analytic hierarchy process, and population density, agricultural population density, vulnerable population, density of arable land, the main road density, building density, industrial output per unit area and per capita annual income of farmers are choiced as eight evaluation factors to process vulnerability assessment of Wenzhou city landslide disaster. Secondly, according to the actual situation, financial revenue and forecast monitoring points are choiced to be two evaluation factors, and a simple method is established to evaluate disaster prevention and reduction capacity of Wenzhou city landslide disaster. On this basis, we combined the landslide hazard assessment, completed landslide risk assessment of the township units in Wenzhou city. Finally, we tested risk assessment results of landslide disaster according to landslides loss caused a heavy rainfall in Wenzhou city.Through this risk assessment, we obtained the vulnerability grade distribution map, distribution map of disaster prevention and reduction capacity, and risk distribution map of landslide disasters in Wenzhou city. Vulnerability distribution basically reflects the population and economic differences of Wenzhou city in the township, distribution of disaster prevention and reduction reflects the township response capacity difference in the landslide disaster, while risk distribution plan reflects the size of the losses caused by landslide. Through the verification of the risk assessment results, we found that the losses caused by landslide disasters, 76.74 percent of the losses have taken place at very high risk or high-risk townships, therefore, we believe that the risk grade distribution more reasonable and reliable, and results satisfacting.