Happening Risk Assessment of Debris Flows after Wenchuan Earthquake in Subao River Valley of Beichuan County, Sichuan, China
The debris flow hazards have caused many damages in Wenchuan earthquake areas.It is of great significance for debris flow disaster prevention and mitigation to assess the happening risks of debris flows in quake-hit areas.In this paper, taking Subao river valley, one of the worst quake-hit areas, as study area, the happening risk assessment of debris flows was conducted based on field survey and remote sensing interpretation.By analyzing characteristics and formation conditions of debris flows in the valley, density of landslides and rock avalanches, distance to the seismogenic fault, formation lithology, ground roughness and hillside gradient were selected as assessment factors.Each of the factors was subdivided into five grades.AHP (Analytic Hierarchy Process) was used to decide the weights of factors.And then the happening risk assessment model was built using the multifactor superposition method and used to assess the happening risk of debris flow in the valley.According to evaluation results, the valley was divided into three areas: high-risk areas, medium risk areas and low risk areas.The high-risk areas concentrated in the middle of the valley, accounting for 17.6% of the valley area.The medium risk areas were in the middle and lower reaches, most of which were located on both sides of the high-risk areas, accounting for 45.3% of the valley area.The rest belonged to low risk areas.The results agreed with the debris flow events following the earthquake in the valley, which showed the method could be used to assess the happening risk of debris flow.And the results also could provide guidance on reconstruction planning and prevention of debris flow in Subao river valley.
risk assessment debris flow geographic information systems Wenchuan earthquake Subao River
X.Z.Chen H.Chen Y.You J.F.Liu
School of Environment and Resource,Southwest University of Science and Technology,Mianyang 621010,Ch Institute of Mountain Hazards and Environment,Chinese Academy of Sciences,Chengdu 610041,China
国际会议
南京
英文
183-187
2014-10-12（万方平台首次上网日期，不代表论文的发表时间）