【摘要】 汶川地震通过诱发滑坡和崩塌产生大量松散固体物质促进了泥石流的暴发,且大多数地震次生泥石流为超大规模,对地震灾后重建造成严重威胁。从区域上进行泥石流灾害危险性评估是目前地震灾区恢复重建和区域经济发展所必须而又紧迫的工作。通过对地震次生泥石流形成条件的分析,提出了一种基于泥石流物源数量,并结合遥感及GIS技术的泥石流危险性快速评估方法。通过在都江堰白沙河59个小流域的应用证明,评估结果与实际灾害情况较吻合,能够为地震灾区泥石流防灾减灾提供参考。此方法适用于地震灾区在短时间内物源突然富集的流域,并且受到遥感图像精度的影响,同时也具有一定时限性,需要根据遥感图像进行周期性更新。此方法能对地震灾区大区域泥石流危险性进行快速评估分级,尤其适用于野外调查无法开展的河流上游区域的泥石流评估。更多还原

【Abstract】 Abundant debris deriving from the landslides and rock avalanches triggered by large earthquakes could significantly alter the characteristics and occurrence frequency of debris flows in the earthquake stricken areas.There is an urgent need for a quick and easy method to assess debris flow hazard to aid the recovery activities by the local residents.Conventional methods are mainly based on field investigations which are time consuming and resources demanding.In addition,as the loose materials are gradually taken away by debris flows,the debris flow occurrence frequency will change with time and more regular updates are needed with the debris flow hazard maps.Therefore,a GIS based system using satellite remote sensing and digital elevation model is proposed in this study.The debris-flow potential index based on the volume of unstable debris is used as the assessment criterion.The proposed method is applied to a case study in the river area affected by the Wenchuan Earthquake 2008.It has been found that the resulted hazard map corresponded well with the observed debris hazards.The validity of the proposed method is depended on the digital data and need regularly update from the latest satellite images with more up-to-date debris accumulation information.更多还原