Connectivity of earthquake-triggered landslides with the fluvial network: Implications for landslide sediment transport after the 2008 Wenchuan earthquake
Connectivity of earthquake-triggered landslides with the fluvial network: Implications for landslide sediment transport after the 2008 Wenchuan earthquake
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DOI：
10.1002/2015jf003718
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发表时间：
2016-04-01
影响因子：
3.9
通讯作者：
Hilton, Robert G.
中科院分区：
文献类型：
--
作者：
Li, Gen;West, A. Joshua;Hilton, Robert G.
评估地震对侵蚀、景观演变和与泥沙相关的灾害的影响，需要了解地震引发的滑坡中释放出来的物质的河流运输。预计滑坡相对于河道的位置将在震后沉积物动力学中发挥重要作用。在这项研究中，我们对汶川7.9级地震引发的滑坡的位置进行了评估，旨在了解滑坡与陡峭的龙门山山脉河流网络的关系。结合滑坡调查图和地貌分析，我们根据尺度关系估计的滑坡数量、滑坡面积和滑坡量来量化滑坡与河道的连通性。我们观察到滑坡-河道连通性具有很强的空间变异性，不同流域的体积连通性从相似到20%到相似到90%不等。这种变异性与决定当地河道密度的地形效应、调节滑坡大小的地震效应(包括发震断层作用)以及可能影响沟道化和滑坡大小的底物效应有关。我们估计，与渠道相连的滑坡总量占同震滑坡总量的43+9/-7%。汶川地震后，细粒(占总滑坡量的90%)可能受滑坡位置的影响更大。
Evaluating the influence of earthquakes on erosion, landscape evolution, and sediment-related hazards requires understanding fluvial transport of material liberated in earthquake-triggered landslides. The location of landslides relative to river channels is expected to play an important role in postearthquake sediment dynamics. In this study, we assess the position of landslides triggered by the M-w 7.9 Wenchuan earthquake, aiming to understand the relationship between landslides and the fluvial network of the steep Longmen Shan mountain range. Combining a landslide inventory map and geomorphic analysis, we quantify landslide-channel connectivity in terms of the number of landslides, landslide area, and landslide volume estimated from scaling relationships. We observe a strong spatial variability in landslide-channel connectivity, with volumetric connectivity (xi) ranging from similar to 20% to similar to 90% for different catchments. This variability is linked to topographic effects that set local channel densities, seismic effects (including seismogenic faulting) that regulate landslide size, and substrate effects that may influence both channelization and landslide size. Altogether, we estimate that the volume of landslides connected to channels comprises 43 + 9/-7% of the total coseismic landslide volume. Following the Wenchuan earthquake, fine-grained (90% of the total landslide volume) may be more significantly affected by landslide locations.