渝东北2014年“8·31”暴雨诱发滑坡遥感解译与分析
An analysis of rainstorm-induced landslides in northeast Chongqing on August 31, 2014 based on interpretation of remote sensing images
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摘要: 2014年8月31日—9月2日重庆市渝东北地区出现一次强降雨过程,引发了大量滑坡,造成了人员伤亡和重大经济损失。为掌握此次降雨诱发滑坡情况,分析滑坡与降雨关系,结合遥感和地理信息系统技术,通过该地区“8·31”暴雨前后的高空间分辨率卫星遥感影像解译,获得了暴雨诱发滑坡分布情况,分析了滑坡发生与降雨、地形之间的关系,研究发现: 渝东北地区复杂的地质构造条件以及由其产生的特有的构造侵蚀地貌格局,不仅使得该区域成为暴雨中心,也导致了该地区降雨型滑坡多发、频发。当日降雨量和累积降雨量分别超过80 mm和160 mm时滑坡开始持续发生; 当日降雨量超过100 mm或累积降雨量超过210 mm时滑坡大量发生。迎风坡且坡度在25°左右斜坡最易发生滑坡。研究认为,在降雨诱发地质灾害易发性分析及预测预报中,应考虑山区地形对局地降雨强度和分布的影响,以提高地质灾害时间和空间分析预测精准度。Abstract: A rainstorm struck northeast Chongqing from August 31 to September 2, 2014. It triggered extensive landslides and resulted in casualties and serious economic losses. To learn the condition of the landslides induced by the rainstorm and analyze the relationship between the landslides and rainfall, this study obtains the distribution of the landslides through the interpretation of high-resolution satellite remote sensing images before and after the rainstorm using RS and GIS techniques. It can be concluded that complicated geological tectonic conditions and corresponding unique tectonic erosion landform pattern make northeast Chongqing become the center of the rainstorm and also lead to the frequent occurrence of rainfall-triggered landslides in this area. Landslides will continuously occur when the maximum daily rainfall and accumulated rainfall exceed 80 mm and 160 mm, respectively, and extensive landslides will occur when the maximum daily rainfall and accumulated rainfall exceed 100 mm and 210 mm, respectively. Furthermore, landslides are the most liable to occur in windward slopes with a gradient of about 25°. Therefore, the regional topography should be taken into account in the analysis and prediction of rainfall-induced geological disasters to improve the accuracy of spatial and temporal prediction and analysis of geological hazards.
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