A Study On GIS-based Hazard Assessment About Earthquake-induced Landslides

"Earthquake-induced landslides" have characteristics of large scale, wide area and serious damage and have been paid attention to. The damage of seismic landslides is extremely serious. The "earthquake-induced landslides" can not only destroy houses, but also break down power station, transmission equipment and other lifeline project. Landslide deposit silts up rivers, brings about secondary flood after dam failure, blocks off roads leading to traffic interruption and directly influences the search and rescue of the wounded and the transportation of relief supplies and rescue personnel. Therefore, risk assessment of landslide stability in the high earthquake intensity regions has an important practical value.This paper is based on practical investigation of "earthquake-induced landslide" disaster in Xishan area in Taiyuan. According to the characteristics of "earthquake-induced landslide" disaster, we determine earthquake intensity, terrain slope, terrain aspect, engineering lithology and average annual rainfall as evaluation indexes, set up disaster distribution database and impact factor database of disaster assessment, and use information method and analytic hierarchy process to do evaluation research of landslide disaster risk. Space analysis function is taken full use in this disaster evaluation. GIS can not only manage relevant information of disaster, but also analyze the relationship between the occurrence of disaster and impact factor from space and time. Therefore, it plays a certain function in determining the probability of the occurrence of disaster, displaying the space distribution characteristics and laws of disaster and reducing the degree of damage that disaster may lead to.This study is built on the actual situation of Xishan area in Taiyuan. Evaluation unit grid is determined as35x35m. Supported by ArcGIS, respectively using information method and analytic hierarchy process calculates comprehensive information value and comprehensive risk value of evaluation unit grid in this study area. Then through the comprehensive value cumulative frequency curve, we can determine searatrix value of disaster risk zoning and further obtain "earthquake-induced landslide" disaster risk zoning map. In the results of information method, risk area and extremely high risk area contain65.91%known "earthquake-induced landslide". By contrast, in the results of analytic hierarchy process, risk area and extremely high risk area contain63.64%known "earthquake-induced landslide". Through comparing results of the two evaluation methods, we can conclude that both information method and analytic hierarchy process can forecast "earthquake-induced landslide" disaster risk of the study area, and predicting results of information method are superior to analytic hierarchy process."Earthquake-induced landslide" disaster risk zoning map of Xishan area in Taiyuan is given in this paper. It can provide reference for land planning, residents property protection standards and earthquake prevention and disaster reduction. Therefore, the disaster risk zoning map has certain practical value.