Characteristic landslide distributions: An investigation of landscape controls on landslide size
Characteristic landslide distributions: An investigation of landscape controls on landslide size
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DOI：
10.1016/j.epsl.2020.116203
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发表时间：
2020-06
影响因子：
5.3
通讯作者：
William G. Medwedeff;M. Clark;D. Zekkos;A. West
中科院分区：
文献类型：
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作者：
William G. Medwedeff;M. Clark;D. Zekkos;A. West
对滑坡侵蚀率的估计和灾害预测需要对滑坡规模的物理控制有充分的了解。在这项研究中，我们试图了解不同景观和强迫事件的特征如何影响滑坡规模在区域尺度上的分布。通过使用数字高程数据的一系列模拟，我们探索了基于力学的滑坡模型的参数空间。与以前的研究一致，我们发现，由于典型山区地形中缺乏大而陡峭的山坡，因此大坡面的破坏并不常见。另一方面，我们发现，小型滑坡的发生受到坡体材料粘聚力的限制，克服了短坡面驱动力较弱的缺点。我们通过对8个真实的同震滑坡清单的频率-大小分布的经验调查来检验我们的模型结果。虽然经验数据有噪声，但我们发现滑坡大小与坡度呈正相关，而PGA对滑坡大小的影响不明显。我们的结论是，滑坡规模分布反映了给定地貌中山坡几何形状的可用分布，而外力(例如地震地面运动)决定了在特定事件期间山坡分布的哪一个子集发生故障。对于给定的地形和强迫事件，存在一个特定的长度尺度，在该尺度上滑坡在统计上是有利的，这导致了特征滑坡尺寸分布的概念。
Estimation of landslide erosion rates and hazard prediction require a firm understanding of the physical controls on landslide size. In this study we seek to understand how the characteristics of different landscapes and forcing events influence the distribution of landslide size at a regional scale. We explore the parameter space of a mechanically-based landslide model through a series of simulations using digital elevation data. Consistent with previous studies, we find that large slope failures are infrequent due to the scarcity of large, steep hillslopes in typical mountainous topography. On the other hand, we find that the occurrence of small landslides is limited by the cohesive strength of hillslope material, which overcomes the weaker driving forces on short slopes. We test our model results with an empirical investigation of frequency-size distributions for eight real co-seismic landslide inventories. Although empirical data are noisy, we find a positive correlation between landslide size and hillslope relief, while the effects of PGA on landslide size are less pronounced. We conclude that landslide size distributions reflect the available distribution of hillslope geometries in a given landscape, and that external forcing (e.g., seismic ground motion) determines which subset of the hillslope distribution fails during a particular event. For a given landscape and forcing event, there is a particular length-scale over which landsliding is statistically favored, leading to the concept of characteristic landslide size distributions.