Geological Hazard Risk Evaluation Research Of Wenchuan County

In view of the complex geological environment and frequent occurrence of collapse, landslide, debris flow in the southwest mountain towns, the Chinese Geological Survey bureau sets the "geological disaster risk control methods and demonstration of Southwest mountain towns"projects . This thesis is based on the project, which selects the Wenchuan County as a case .According to characteristics of geological disasters in Wenchuan County; it uses the GIS technology to carry out the geological hazards evaluation of the Wenchuan County. After the study, the paper obtained the following achivements.1. According to geological disasters before and after the earthquake, it founds that geological hazards after the earthquake in Wenchuan County are in larger quantities and wider distribution than the geological hazards before the earthquake . Applying the ILWIS soft to analyses, it gets the relation between geological disaster and topography, lithology, geological structure, landuse, rainfall, earthquakes, and human engineering activities factors.2. After analyzing the previous achievement, it summarizes most of the indicators that are commonly used for risk assessment of geological hazards. Considering the Wenchuan County belong to the small area and large-scale evaluation, it establishes the risk evaluation indicator system for sliding masses, debris flow. It applies weight to the indicator using the AHP method.3. On account of the strengths and shortcomings of the information-weight model, it proposes the improved information-weight models and implements model in GIS software. It gives detailed procedure of how to apply the improved information-weight in the ILWIS software for the geological hazard assessment and analysis. 4. It obtains the final geological hazard hierarchy map after dividing the risk index map into four classes .By analyzing risk index and risk classification map, we can get that most of the historical geological hazards are in the medium-high risk region, which proves the feasibility of improved information-weight model, and it also proves the applicability and reliability of indicators system.