Why so few? Landslides triggered by the 2002 Denali earthquake, Alaska
Why so few? Landslides triggered by the 2002 Denali earthquake, Alaska
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DOI：
10.1016/j.quascirev.2014.04.032
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发表时间：
2014-07-01
影响因子：
4
通讯作者：
van der Meer, Freek D.
中科院分区：
文献类型：
--
作者：
Gorum, Tolga;Korup, Oliver;van der Meer, Freek D.
2002年阿拉斯加州M-w 7.9级德纳里断层地震提供了一个无与伦比的机会，可以定量详细地研究冰川化地形中强地震震动对区域山坡质量消耗的反应。我们提出了类似1580个同震边坡破坏的第一个详细清单，其中约20%发生在大型山谷冰川之上，基于多时遥感数据的制图。我们发现，德纳里地震在断层破裂的窄走廊上产生的滑坡至少比8级地震的经验预测少一个数量级，尽管有足够陡峭和解剖的山地地形，容易发生频繁的边坡破坏。为了探索对区域同震滑坡减少程度的潜在控制，我们将我们的数据与我们为冰川周围和以前冰川地形（即2010年9月）和智利Aysen峡湾（2007年M-w 6.2）最近两次地震编制的清单进行了比较。这些事件中的断层运动与德纳里地震类似，主要是沿近垂直断层的走滑偏移。我们的比较得到了非常相似的同震滑坡模式，这与断层类型、几何形状和动态破裂过程而不是广泛的冰川覆盖是这些地震中区域山坡侵蚀反应的一级控制因素的观点是一致的。我们得出的结论是，仅从地震震级估计同震斜坡沉积物输入到沉积物级联的数量仍然存在很大问题，特别是如果涉及冰川化地形。(C) 2014 Elsevier Ltd.版权所有。
The 2002 M-w 7.9 Denali Fault earthquake, Alaska, provides an unparalleled opportunity to investigate in quantitative detail the regional hillslope mass-wasting response to strong seismic shaking in glacierized terrain. We present the first detailed inventory of similar to 1580 coseismic slope failures, out of which some 20% occurred above large valley glaciers, based on mapping from multi-temporal remote sensing data. We find that the Denali earthquake produced at least one order of magnitude fewer landslides in a much narrower corridor along the fault ruptures than empirical predictions for an M 8 earthquake would suggest, despite the availability of sufficiently steep and dissected mountainous topography prone to frequent slope failure. In order to explore potential controls on the reduced extent of regional coseismic landsliding we compare our data with inventories that we compiled for two recent earthquakes in periglacial and formerly glaciated terrain, i.e. at Yushu, Tibet (M-w 6.9, 2010), and Aysen Fjord, Chile (2007 M-w 6.2). Fault movement during these events was, similarly to that of the Denali earthquake, dominated by strike-slip offsets along near-vertical faults. Our comparison returns very similar coseismic landslide patterns that are consistent with the idea that fault type, geometry, and dynamic rupture process rather than widespread glacier cover were among the first-order controls on regional hillslope erosional response in these earthquakes. We conclude that estimating the amount of coseismic hillslope sediment input to the sediment cascade from earthquake magnitude alone remains highly problematic, particularly if glacierized terrain is involved. (C) 2014 Elsevier Ltd. All rights reserved.