The Analysis And Forecast Of Geological Disasters Induced By The Precipitation Of The Landing Typhoon

China has a vast territory,complicated geological and geographical conditions,and a huge difference in climate conditions,which belongs to one of the countries with many geological disasters.The typhoon is one of the main rainstorm system in our country,the period of typhoons inducing geological disasters,typhoon heavy rainfall may lead to geological disasters landslides,mudslides and landslides and other geological disasters.The data used in this papercomes from"national geological disaster database"and"the Ministry of Land and Resources".And also uses typhoon rainfall data and geographic information data.By using the statistical method to analysis of temporal and spatial distribution of geological disasters caused by typhoon.By adopting the method of curve to establish rainfall threshold equation that the geological disasters induced by typhoon precipitation.Analysis of the characteristics of typhoon precipitation which caused geological disasters and compared with the non-typhoon precipitation.In addition,the prone area of Typhoon Rainfall Type geological disaster is divided.On this basis,the frequency ratio method is used to study the Susceptibility of geological disasters in this area.According to the data that the geological disaster from 1990 to 2015,the time of occurrence of geological disasters in China are mainly concentrated in May to September.For geological disasters induced by typhoon precipitation,mainly occurred in the June to September.The geological hazards caused by typhoon heavy rainfall are mainly concentrated in the coastal areas of Zhejiang,Fujian and Guangdong.The most frequent type of geologic hazards is the landslides,and the most northern one is the middle part of Liaoning province and the central part of Yunnan.The geological disasters caused by non-typhoon precipitation are located in Yunnan,Guizhou,Sichuan,Chongqing and other places in the southwest of China.Geological disasters caused by typhoon precipitation are more closely related to the precipitation on the day,and the rainfall on the day and maximum intensity of rain were generally higher than the non-typhoon rainfall induced.Under the same rainfall duration,the precipitation induced geological hazard in typhoon area needs greater average rainfall intensity than that in non-typhoon area.The threshold equation of typhoon rainfall threshold which caused geological disasters was I=10.9D^-0.74.When the the cumulative rainfall and critical rainfall are all greater than 24mm,or the cumulative rainfall is more than 33mm,which arethe necessary condition for typhoon precipitation to induce geological disasters.The distribution of rainfall level in the day of non-typhoon precipitation is relatively scattered,so any magnitude of rainfall on the day has a weak impact on the occurrence of disasters.The accumulated rainfall in the early stage is closely related to the occurrence of geological disasters.The multiple linear regression equation established by accumulated rainfall on the first 7 days can better reflect the possibility of geological hazard.When the cumulative rainfall is less than 200mm on the 7 day,the regression equation has better fitting effect.For geological disasters which caused by non-typhoon precipitation,the single day rainfall in the first 1 days of the first 5days of occurrence has a great influence on the occurrence and development of the disaster.The relationship between average rainfall intensity and rainfall duration is established based on the case of Jiangxi.Compared with the global threshold of precipitation,the average rainfall intensity is usually greater in the study area.Based on the typhoon precipitation,geological disaster data and geographical disaster information,the GIS tool was used to analyze the susceptibility of geological hazards in the typhoon-affected area,and the geological typhoon-disaster-prone area was obtained.The area is,from Liaoning Province to Yunnan Province,a large area of eastern China.The geological disaster susceptibility index in the three provinces of Zhejiang,Fujian and Jiangxi was calculated using the frequency ratio method,which indicatethat the index shows an tendency that low value in the central part and a high value in the surrounding area of the three provinces.Based on the contents of Chapters 3 and 4,this study established a risk identification process of typhoon rainfall-based geological disaster.In the process of geological disasters induced by typhoon precipitation,the area with a geological disaster susceptibility index greater than 3 is the main risk warning area;when simultaneously satisfying the relationship between cumulative precipitation and critical precipitation of typhoon rainfall-type geological disasters,and the regression threshold equations of average rainfall intensity I and rainfall duration D,it indicates that there is a risk of geological disasters in this area.Precipitation is the driving factor for the occurrence of geological disasters.However,in real work,in addition to considering the impact of precipitation,it is also necessary to actually inspect the factors such as the environment of the disaster site,the conditions of the geological landscape,and the vegetation coverage.In this paper,did not involve the study of hazard factors such as water systems,fractures,and surface curvature.Therefore,in the future work,a more comprehensive study of the causes of geological disasters should be conducted to provide scientific support for disaster prediction.