Examination of relation with tsunami behavior reconstructed from on-site sequence photographs, topography, and sedimentary deposits from the 2011 Tohoku-oki tsunami on the Kamikita Plain, Japan
Examination of relation with tsunami behavior reconstructed from on-site sequence photographs, topography, and sedimentary deposits from the 2011 Tohoku-oki tsunami on the Kamikita Plain, Japan
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DOI：
10.1016/j.margeo.2014.08.009
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发表时间：
2014-12-01
期刊：
影响因子：
2.9
通讯作者：
Isono, Takahiro
中科院分区：
文献类型：
--
作者：
Koiwa, Naoto;Kasai, Mio;Isono, Takahiro
本报告基于对2011年东北冲海啸的连续数字照片、海啸沉积物的空间分布以及使用数字高程模型（DEM）重建的地形条件的解释，对日本东北部三泽海岸的海啸行为进行了研究。在研究区，仅发生了一次上升流和上升流。海啸洪水开始后几分钟，上升流达到最大淹没高度。地形特征，如梯田，切割山谷，沿海低地和人工海堤限制了海啸流量。桑迪海啸存款分布仅限于距离海岸线几百米。沉积物显示内陆变薄和变细。它们还表明在较高表面的方向上变薄和变细。厚层沉积物局部分布在海滩脊和海堤之间的盆地区域，在上升流过程中经过几分钟的反复加速和减速，形成了多层逆级配和正级配。在海啸发生后的急流集中区，海啸沉积物的沉积不仅受到上升流的影响，而且还受到急流的影响。(C)2014爱思唯尔有限公司版权所有。
This report presents an examination of tsunami behavior for the Misawa coast of northeastern Japan based on interpretations of sequential digital photographs of the 2011 Tohoku-oki tsunami, spatial distribution of tsunami deposits, and topographical conditions reconstructed using the Digital Elevation Model (DEM). In the study area, run-up flow and then backwash flow occurred only once. Run-up flow reached maximum inundation height several minutes after tsunami flooding started. Topographic features such as terraces, dissected valleys, coastal lowlands, and artificial seawall constrained the tsunami flow. The sandy tsunami deposit distribution is limited to several hundred meters from the shoreline. Deposits show inland thinning and fining. They also indicate thinning and fining in the direction of higher surfaces. Thick deposits, which are distributed locally in the basin area between the beach ridge and the seawall, exhibited multiple layers of inverse and normal grading formed by repeated acceleration and deceleration for several minutes during the run-up flow. In the area with concentrated backwash flow after the tsunami struck, the sedimentation for tsunami deposits was affected not only by the run-up flow, but also by the backwash flow. (C) 2014 Elsevier B.V. All rights reserved.