Study On Division Of Geological Disasters Susceptibility And Meteorological Forecasting And Warning Of She County Anhui Province

She County is located in the south of Anhui Province, within the region strongly terrain cutting, high mountains and steep slopes, fragile regional geological environment, coupled with irrational human activity which result further deterioration of geological environment. Under rainfall, it will cause a lot of geological disasters. Geological disasers in Shenxian have the characteristic of “ quantity, broad, suddenly, big disaster losses” and so on, so prevention and control mechanisms and monitoring and early warning of geological disasters were particularly important. But current disaster warning was over emphasize weather warning, can not combine rainfall to the geological conditions, the precision and accuracy of early warning and forecast accuracy is not high.In this paper, based on 502 historical geological disasters and their rainfall data, deeply studied the division of geological disasters susceptibility and the relationship between rainfall and the distribution of time and space of rainfall- induced geological disasters, completed the division of geological disasters susceptibilityin study areas, determined the rainfall thresholds expression, created a regional geological disaster forecasting and warning rainfall method, realized the geological disaster weather warning. The research results in this paper are as follows:(1)The main geological disasters of She County were landslides, collapses and unstable slopes, which were distributed in towns of east or northeast She County. Geological disasters were mainly along the controllability mountains and faults, clearly distributed along the roads. They had a characteristic of inhomogeneity in low-altitude areas. The intensity of human activity and the amount of rainfall were significantly positive correlation to the development of geological disasters.(2)Choosing 10 factors that impact regional geological disasters(elevation, slope height, slope, slope shape, lithology, fault distribution, rivers cutting, vegetation coverage,road density, residential distribution), established the index system of susceptibility of geological hazards. Density and breakpoints of historical geological hazards in each degree of indexes were chosen as the standard of secondary classification of indexes, and then quantified and normalized the index.(3)Using the Logistic regression model, choosing historical disasters and random non-disasters point in the study area as the statistical sample, established the evaluation model of susceptibility of geological disasters in study area and got the probability formula of susceptibility of She County geological disasters(Pa). According to the susceptibility of geological disasters Pa, geological disasters susceptibility zoning map of She County can be drawed. The geological disasters susceptibility zoning of She County fit the consistent fact of geological disasters, so the model worked well.(4)Got the probability formula of rainfall-induced-only geological disasters(Pb) and the expression evaluation of critical rainfall. Through the statistical analysis of rainfall- induced geological disasters’ historical data, it showed that the accumulative rainfall and daily rainfall had a great impact on the development of geological disasters. C hoosing the early accumulative rainfall and daily rainfall indexes of evaluation, a logistic regression model of geological disasters induced by rainfall only can be established to determine the scope of the accumulative rainfall and to get the probability formula of rainfall- induced-only geological disasters(Pb) and the expression evaluation of critical rainfall.(5)Established the meteorological early warning model of geological disasters. This paper used probability(Pa) of the geological disaster-prone area as a regional index and the value of rainfall- induced geological disasters univariate probability(Pb) as cofactors of time and space. Though Pa multiplied by Pb, it would get the real-time forecasting probability value Pc of geological disasters. Based on the value of Pc, spatial and temporal rainfall- induced landslide warning level was divided into five different grades corresponding to different levels of defense.