Relationship between the accumulation of sediment storage and debris-flow characteristics in a debris-flow initiation zone, Ohya landslide body, Japan
Relationship between the accumulation of sediment storage and debris-flow characteristics in a debris-flow initiation zone, Ohya landslide body, Japan
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DOI：
10.5194/nhess-17-1923-2017
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发表时间：
2017-11
影响因子：
4.6
通讯作者：
F. Imaizumi;Y. Hayakawa;N. Hotta;H. Tsunetaka;O. Ohsaka;S. Tsuchiya
中科院分区：
文献类型：
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作者：
F. Imaizumi;Y. Hayakawa;N. Hotta;H. Tsunetaka;O. Ohsaka;S. Tsuchiya
抽象的。泥石流通常发生在陡峭的山区通道中，由于其破坏力大、传播距离长和速度高，因此可能极其危险。然而，它们在起始区中的特性可能会受到储存器累积条件的时间变化的影响（即，河道坡度和蓄水量）与山坡沉积物供应和泥石流对沉积物的排空有关。因此，我们研究了流动特性和存储在日本Ohya滑坡体的泥石流起始带的积累条件之间的关系，使用各种方法，包括物理分析，定期地面激光扫描（TLS）调查，和现场监测。研究表明，由于地形陡峭，半饱和泥石流和全饱和泥石流都是泥石流起动区重要的水文地貌过程。流量的主要类型随时间变化，并受到存储量和降雨模式的影响。当总库容为15000 m3时，以完全饱和流为主。泥石流形成的河道地形反映了泥石流事件中的主要流态。部分饱和泥石流倾向于形成较陡的河道断面（22.2-37.3°），而完全饱和泥石流倾向于形成较平缓的河道断面（
Abstract. Debris flows usually occur in steep mountain channels and can be extremely hazardous as a result of their destructive power, long travel distance, and high velocity. However, their characteristics in the initiation zones, which could possibly be affected by temporal changes in the accumulation conditions of the storage (i.e., channel gradient and volume of storage) associated with sediment supply from hillslopes and the evacuation of sediment by debris flows, are poorly understood. Thus, we studied the relationship between the flow characteristics and the accumulation conditions of the storage in an initiation zone of debris flow at the Ohya landslide body in Japan using a variety of methods, including a physical analysis, a periodical terrestrial laser scanning (TLS) survey, and field monitoring. Our study clarified that both partly and fully saturated debris flows are important hydrogeomorphic processes in the initiation zones of debris flow because of the steep terrain. The predominant type of flow varied temporally and was affected by the volume of storage and rainfall patterns. Fully saturated flow dominated when the total volume of storage was 15 000 m3. Debris flows form channel topography which reflects the predominant flow types during debris-flow events. Partly saturated debris flow tended to form steeper channel sections (22.2–37.3°), while fully saturated debris flow tended to form gentler channel sections (