Preservation potential of tsunami deposits on arid siliciclastic coasts
Preservation potential of tsunami deposits on arid siliciclastic coasts
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干旱硅质碎屑海岸海啸沉积物的保存潜力
DOI：
10.1016/j.earscirev.2013.07.009
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发表时间：
2013
影响因子：
12.1
通讯作者：
H. Bahlburg
中科院分区：
文献类型：
--
作者：
M. Spiske;J. Piepenbreier;C. Benavente;H. Bahlburg
在过去的二十年中，特别是在2004年印度洋海啸之后，进行了大量的海啸后调查。这些研究记录了各种沉积和侵蚀特征，这些特征可以归因于已知事件。然而，问题出现了，这些结构是短暂的，还是有可能被保存在地质记录中。本文综述了影响秘鲁泥质到砂质硅质海啸沉积的变化。海啸发生后的头几个月，我们分别对钦博特（1996年）、卡马纳<e:1>（2001年）和皮斯科-帕拉卡斯（2007年）进行了调查。在这里，我们描述了我们在2007年和2008年重新调查中观察到的变化。人们早就认识到，陆上海啸沉积物可能受到地表作用、构造运动和人为蚀变的影响。地震引起的隆起或下沉可能分别使海啸沉积物受到侵蚀或掩埋。在快速下沉的沿海地区快速掩埋可以加强保存。如果最后一个或最靠近陆地的波浪的沉积物不受随后的海啸波的侵蚀，它们可能被优先保存下来；然而，内陆地区也容易受到地面改造的影响，包括由风和人类造成的改造。这里回顾的秘鲁例子表明，干旱海岸海啸沉积物的保存取决于迄今为止所认为的更为复杂的相互作用。这些包括沉积物类型、粒度、沉积背景、同震运动、生物扰动、风和人为改变。在一个例子中，海啸的所有痕迹都被洪水和海浪抹去或重新塑造了。在另一个例子中，海啸反冲后海岸平原上的碎屑在事件发生后立即被风成沙磨圆并磨损。风成过程也使海啸冲刷变得平滑和充实。相比之下，在某些地区，泥泞的海啸沉积物逃脱了风的侵蚀，可能是因为它们具有更强的凝聚力。在另一个例子中，0.5米的同震隆起不足以阻止海浪带走覆盖在沿海沼泽上的海啸沙层。因此，现代海岸上埋藏的海啸沉积物记录可能不能完全代表这些地区对海啸灾害的脆弱性。
Numerous post-tsunami surveys have been conducted in the last two decades, especially since the 2004 Indian Ocean tsunami. These studies have documented a variety of characteristic sedimentary and erosional features that can be ascribed to known events. Nevertheless, the question arises whether these structures are just ephemeral or have a potential to be preserved in the geological record. This review describes the changes that have affected muddy to sandy siliciclastic tsunami deposits in Peru. Each of these was surveyed in the first months after the tsunami: Chimbote (1996), Camaná (2001) and Pisco-Paracas (2007). Here, we describe the changes we observed during re-surveys in 2007 and 2008.It has long been recognized that onshore tsunami deposits may suffer from surficial processes, tectonic movements and anthropogenic alteration. Earthquake-induced uplift or subsidence may subject a tsunami deposit to erosion or burial, respectively. Quick burial in rapidly subsiding coastal areas may enhance preservation. Deposits of the last or most landward-reaching wave may be preferentially preserved if they escape erosion by subsequent tsunami waves; however, inland areas are also vulnerable to subaerial reworking, including by wind and by humans.The Peruvian examples reviewed here show that the preservation of arid-coast tsunami deposits depends on interactions that are more complex that hitherto perceived. These involve sediment type, grain size, depositional setting, co-seismic movement, bioturbation, winds, and anthropogenic modification. In one example, all traces of the tsunami have been removed or reworked by flash floods and ocean waves. In another example, clasts on a coastal plain from tsunami-backwash began to be rounded and abraded by eolian sands immediately after the event. Eolian processes also smoothed and filled tsunami scours. By contrast, muddy tsunami deposits in certain areas escaped erosion by wind, probably because of their greater cohesion. In still another example, 0.5 m of co-seismic uplift was not enough to prevent ocean waves from removing a tsunami sand sheet that had mantled a coastal marsh. The buried record of tsunami deposits on modern coasts may therefore not fully represent the vulnerability of these regions to tsunamigenic hazards.
TsuSedMod 反演模型应用于 2004 年苏门答腊岛和 2006 年爪哇海啸的沉积物以及对估计古海啸流动参数的影响
影响因子：
2.8
作者：
Spiske;Bahlburg;Roskosch;Amijaya
通讯作者：
Amijaya