Dynamic controls on erosion and deposition on debris-flow fans
Dynamic controls on erosion and deposition on debris-flow fans
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DOI：
10.1130/g32103.1
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发表时间：
2011-09
期刊：
影响因子：
5.8
通讯作者：
P. Schuerch;A. Densmore;N. Rosser;B. McArdell
中科院分区：
文献类型：
--
作者：
P. Schuerch;A. Densmore;N. Rosser;B. McArdell
泥石流是山区最危险和最不可预测的地表过程之一。这部分是因为对泥石流侵蚀和沉积的了解很少，导致了水流行为、河道稳定性和多股水流的连续效应的重大不确定性。在这里，我们应用地面激光扫描和流量过程线分析，以量化的侵蚀和沉积在一系列的泥石流在伊尔格拉本，瑞士。我们确定流深作为一个重要的控制模式和规模的侵蚀，而沉积更多的是由流动边缘的几何形状。水流深度和侵蚀之间的关系在河段尺度和整个扇尺度上都是可见的。最大流深是泥石流前端排放和预流通道横截面几何形状的函数，这种双重控制会产生复杂的相互作用，影响长期通道稳定性，使用扇地层重建过去的泥石流制度，泥石流灾害的可预测性。
Debris flows are among the most hazardous and unpredictable of surface processes in mountainous areas. This is partly because debris-flow erosion and deposition are poorly understood, resulting in major uncertainties in flow behavior, channel stability, and sequential effects of multiple flows. Here we apply terrestrial laser scanning and flow hydrograph analysis to quantify erosion and deposition in a series of debris flows at Illgraben, Switzerland. We identify flow depth as an important control on the pattern and magnitude of erosion, whereas deposition is governed more by the geometry of flow margins. The relationship between flow depth and erosion is visible both at the reach scale and at the scale of the entire fan. Maximum flow depth is a function of debris-flow front discharge and pre-flow channel cross-section geometry, and this dual control gives rise to complex interactions with implications for long-term channel stability, the use of fan stratigraphy for reconstruction of past debris-flow regimes, and the predictability of debris-flow hazards.