The classification of landslide dams based on duration time until overtopping erosion

Abstract

The viable countermeasures to prevent damages from overtopping erosion of landslide dams depend largely on duration time until overtopping erosion. In this study, we collected and organized resources relevant to the duration times of past landslide dams and defined a clear relationship among basin area, reservoir storage, and duration time. Therefore, the viable countermeasures were organized by basin area and reservoir storage of the dam-forming position based on duration time. Duration time was classified into five stages based on basin area and reservoir storage. According to this classification, it is possible to predict approximately duration time until overtopping erosion for the scale of landslide dam in each point of the basin. Then, it is possible to consider the viable countermeasures of previous landslide dams and necessary advance preparations. However, the duration time of landslide dams caused by earthquakes had a low accuracy of classification compared to by heavy rain regarding consequences to factors other than the basin area and reservoir storage of the dam-forming position.