Hazard Assessment On Secondary Geological Disasters Of Earthquake Using Bivariate Statistical Analyses

Earthquake causes social and economic effects, devastatingly. It always triggers lots of secondary geological disasters, such as landslides, debris flow and so on. There are more and more researches on earthquake and secondary disasters. Meanwhile, more technical methods are used. Yushu earthquake generated surface fracture, which induced many secondary disasters, such as landslides, unstable slopes, etc. We studied on the researches and hazard assessment methods at home and abroad. Then, bivariate statistical analyses are used for the hazard assessment on secondary geological disasters of Yushu earthquake.The main contents and results of this paper are:a. A variety of materials of the study area were acquired, including the secondary geological disasters. We extracted basic topographic factors slope, elevation and aspect from DEM of the study area. Then we analyzed the relationship between the factors and geological disasters. We acquired remote sensing image, such as ETM, in order to extract rivers, roads, vegetation cover, landslides, debris flow and other geological disaster information.b. WOE, one of bivariate statistical analyses, are used on sensitivity assessment of the study area. We calculated the sensitivity index of slope, elevation, aspect, faults, rivers, vegetation coverage, lithology, by ARCGIS spatial analysis functions. Then through overlay analysis of these factors, sensitivity zoning can be achieved.c. Roads and residential areas of the study area were analysed. These data were be used to carry out hazard assessment, based on sensitivity analysis. And natural breakpoint method were used to finish the regionalization map of geological disasters.