Effects of the 2011 Tohoku‐oki tsunami and human activities on long‐term coastal geomorphic development in northeastern Tohoku, Japan
Effects of the 2011 Tohoku‐oki tsunami and human activities on long‐term coastal geomorphic development in northeastern Tohoku, Japan
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2011年东北冲海啸和人类活动对日本东北部沿海地貌长期发展的影响
DOI：
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发表时间：
2023
影响因子：
3.3
通讯作者：
N. Koiwa
中科院分区：
文献类型：
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作者：
Haruki Imura;Kazuhisa Goto;Kenta Minamidate;N. Koiwa
2011年的东北海啸导致了日本东北部太平洋沿岸的大规模地形变化。海啸袭击该地区已经10多年了。今天，由于重建工作，很少有地方可以连续监测海啸后的自然地形变化。在这项研究中，作者基于航空照片、挖掘和使用探地雷达在日本青森县大须贺海岸进行的地下勘探，调查了2011年海啸以及海啸前后50年间自然和人为活动造成的地形变化。这个地点很罕见，因为它是一个保护区，工程活动很少，而且很肤浅，这使得它适合连续观测海啸前、海啸中和海啸后的地形变化。研究结果表明，2011年海啸波造成了较大的地形变化，海啸产生的沉积和侵蚀特征可以分别识别为沙丘上的海啸沉积物和侵蚀通道。在海啸后阶段，海岸的沙量迅速自然恢复。海啸沉积物和侵蚀河道在地震发生10年后仍完好地保存在地下。然而，沙丘的动力运动是在海啸之后开始的。这种变化是由于沿海森林的人工砍伐，而不是海啸对海岸的影响。我们的研究结果首先表明，在海啸灾区的海滩和沙丘的地下，不仅古海啸的沉积特征，而且古海啸的侵蚀特征也有可能被保留下来。此外，与海啸影响相比，森林砍伐等人为活动对海岸地貌稳定性的破坏更为严重：海岸现在处于与海啸前不同的状态。
The 2011 Tohoku‐oki tsunami caused large‐scale topographic changes along the Pacific coast of northeastern Japan. More than 10 years have passed since the tsunami waves struck the area. Today, because of reconstruction work, very few places exist where natural post‐tsunami topographic changes can be monitored continuously. For this study, the authors investigated topographic changes caused not only by the 2011 tsunami but also by natural and artificial activities during the 50 years before and after the tsunami based on aerial photographs, excavations and subsurface explorations using ground‐penetrating radar at the Osuka coast in Aomori prefecture, Japan. The site is rare because it is a protected area with few and superficial engineering activities, making it suitable for continuous observation of pre‐tsunami, syn‐tsunami and post‐tsunami topographic changes. The findings indicate that the 2011 tsunami waves generated large topographic changes: depositional and erosional features produced by the tsunami can be recognized, respectively, as tsunami deposits and erosional channels across the sand dunes. During the post‐tsunami phase, the sand volume at the coast quickly recovered naturally. Tsunami deposits and the erosional channels were well preserved underground even at 10 years after the event. However, dynamic movement of the dunes started after the tsunami. The shifting was attributable to the artificial clearing of coastal forests rather than the tsunami effects on the coast. Our results first indicate not only that the sedimentary features of paleo‐tsunamis but also the erosional features have some probability of being preserved in the subsurface of the beach and sand dunes at tsunami‐affected areas. Also, artificial activities such as deforestation are much more crucially undermining of the stability of the coastal geomorphology than the tsunami effects: the coast is now reaching a different status from its pre‐tsunami situation.
影响因子：
3.5
作者：
Wessel, P.;Luis, J. F.;Tian, D.
通讯作者：
Tian, D.