Liquefaction as an important source of the A.D. 2011 Tohoku-oki tsunami deposits at Sendai Plain, Japan
Liquefaction as an important source of the A.D. 2011 Tohoku-oki tsunami deposits at Sendai Plain, Japan
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液化是日本仙台平原公元 2011 年东北冲海啸沉积物的重要来源
DOI：
10.1130/g33123.1
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发表时间：
2012
期刊：
影响因子：
--
通讯作者：
S. Fujino
中科院分区：
文献类型：
--
作者：
K. Goto;D. Sugawara;Tomoya Abe;T. Haraguchi;S. Fujino
本文通过对2011年东北冲海啸前后仙台平原的实地调查和数字高程模型数据分析，阐述了海啸沉积物的地形变化、恢复过程以及沉积物来源。我们发现，沉积在陆地上的沉积物数量大约是海滩沉积物侵蚀量的四倍。大量的沉积物沉积在所研究的样带可能来自液化。这一结果表明，排气沉积物可能是海啸沉积物的一个重要来源，如果液化产生的强地面运动的近场地震。相反，在海滩观察到轻微的侵蚀，海啸后三个月内重建了海滩护堤。此外，在海啸发生后13天内，切入海滩的侵蚀河道已被沙子填满。因此，尽管海啸后陆地上的小冲刷遗迹可能会长期存在，但预计仙台海岸沿着的近岸区不会保留海啸的沉积记录。
This paper describes the topographic change and the recovery process, as well as the sediment sources, for tsunami deposits based on field surveys and analysis of digital elevation model data before and after the A.D. 2011 Tohoku-oki tsunami at the Sendai Plain, Japan. We found that the amount of sediment deposited on land was approximately four times greater than the eroded volume of sediment at the beach. Large amounts of the sediments deposited at the studied transect probably originated from liquefaction. This result suggests that the vented sediments might have been an important source of the tsunami deposits if liquefaction is generated by the strong ground motion of a near-field earthquake. In contrast, minor erosion was observed at the beach, and the beach berm was rebuilt within three months after the tsunami. Moreover, the erosional channel that had cut into the beach had been filled by sand within 13 days after the tsunami. Therefore, it is not expected that a sedimentary record of the tsunami will be preserved in the nearshore zone along the Sendai coast, although remnants of small scours on land might remain long after the tsunami.