Geological Hazard Assessment Of Longnan City Based On

All kinds of geological hazards happened in our country,because the vast territory, complex geological and topography conditions, geological Structure.In recent years, large-scale geological disasters often happened,Wenchuan earthquake, Yushu earthquake, Ya’an earthquake and Zhouqu landslides and other disasters caused huge casualties and property losses. For this purpose the establishment of scientific and long-term prevention mechanism is very urgent.In this paper, Longnan City as the study area ande geological disasters in Longnan for the study objectives. Analied the regional geography, basic geology, geomorphology, hydrology, meteorology, vegetation and human activity, and descriped the geological disasters situation in Longnan. Select slope, aspect, the relative elevation, lithology, vegetation, distance from the fault, the distance from the river, rainfall and human factors as the assessment index for the building of evaluation system. Used fuzzy comprehensive evaluation method and AHP overlay method to assess the geological hazard in Longnan, and the two methods were compared. Geological disaster vulnerability of the study area were evaluated, selected population, gross domestic product (GDP), fixed asset investment as assessment indexes. On the basis of geological hazard evaluation, get geological disaster risk evaluation results of the study area. Made a brief introduction of the current practice in the prevention and control of geological disasters. In this paper, get the following conclusions:(1)Analysis the number of Longnan geological hazards, size, distribution, causes, the results showed lots of mudslides happened in Longnan, followed by a landslide, the number of the two disaster points accounts for of 92.4%. About the spatial distribution of geological disasters, the most developed Wudu, Wenxian, Taichang and Lixian, geological hazards and development of these four counties accounted for 81.7 percent of the region。(2)Using AHP method and fuzzy comprehensive evaluation method for Longnan conducted geological hazard assessment and zoning, and the evaluation results of the two methods were compared and analyzed, after comparing the situation with the current situation and development of geological disasters believe, fuzzy comprehensive evaluation method for geological hazard evaluation have better results. Results of the evaluation is a high risk of geological disasters in Wen County district accounted for the highest, followed by Lixian, Wudu. This is basically consistent with the status quo of geological hazards, the evaluation shows that the assessment index is appropriate and the methods are reasonable。(3)The results of geological disaster vulnerability assessment indicate that the maximum degree of social and economic vulnerability of counties is in Wudu, and followed by Xihe, Lixian, Hui County, Wen County, then Liangdang,Kang County and Tanchang. According to county Vulnerability proportion made Longnan geological hazards vulnerability map in ArcGIS.(4)On the basis of geological hazard assessment and vulnerability assessment, the geological disaster risk evaluation results of the study area are divided into three levels. The geological disaster high-risk areas are in Xihe, Lixian and Wudu District, medium-risk located in Wen County and Hui County,low-risk areas are located in Liangdang, Kang County and Tanchang.