TY - JOUR
T1 - Sediment transport due to the 2011 Tohoku-oki tsunami at Sendai
T2 - Results from numerical modeling
AU - Sugawara, Daisuke
AU - Takahashi, Tomoyuki
AU - Imamura, Fumihiko
N1 - Funding Information:
We sincerely acknowledge Dr. Bruce E. Jaffe for his thorough review of the manuscript. His critical comments and useful suggestions were valuable in the revision of this paper. We appreciate another anonymous reviewer and the guest editor Kazuhisa Goto for providing important comments and questions, which we used to improve the paper. The majority of the figures were created using the Generic Mapping Tools (GMT; Wessel et al., 2013 ). This study was supported by and performed as part of the Strategic Program for High-Performance Computing Infrastructure (HPCI; hp120312), which is sponsored by the Ministry of Education, Culture, Sports, Science and Technology in Japan.
Publisher Copyright:
© 2014 Elsevier B.V.
PY - 2014/12/1
Y1 - 2014/12/1
N2 - Numerical modeling of sediment transport on the Sendai Plain in northeast Japan, which was caused by the 2011 Tohoku-oki tsunami, was performed to investigate why onshore tsunami deposits included small amounts of marine materials and to explain the gap between the maximum inland extent of the recognizable sand layer and the limit of inundation. The simulation results generally corresponded with the thicknesses of the deposits observed in the field by previous studies. The simulation revealed that the tsunami caused a significant amount of erosion on the beach and in the coastal forest; however, erosion was significantly limited on the offshore seafloor. In addition, the bore of the highest tsunami wave offshore limited the amount of suspended sediment due to a steep bathymetric profile of the shoreface and a moderate initial drop in water level prior to the arrival of the bore. This resulted in limited suspension and shoreward advection of the sediments and a minor contribution of the seafloor sediments to the onshore tsunami deposit. Visualization of the onshore sediment transport indicated that the sediment transport was significantly affected by artificial topographic features. The flow speed and height varied across the topographic highs, and sediments were trapped on the seaward side of these highs. In coastal areas, the sediment supply was limited due to the presence of engineered dikes along the coast. In inland areas, embankments of paved roadways caused increased deposition on the seaward sides of the embankments and less deposition on the leeward sides of the embankments. Although some aspects of the relevant physics were not fully implemented in the model, in which uncertainties exist, the results may explain the processes and consequences of sedimentation from a tsunami event.
AB - Numerical modeling of sediment transport on the Sendai Plain in northeast Japan, which was caused by the 2011 Tohoku-oki tsunami, was performed to investigate why onshore tsunami deposits included small amounts of marine materials and to explain the gap between the maximum inland extent of the recognizable sand layer and the limit of inundation. The simulation results generally corresponded with the thicknesses of the deposits observed in the field by previous studies. The simulation revealed that the tsunami caused a significant amount of erosion on the beach and in the coastal forest; however, erosion was significantly limited on the offshore seafloor. In addition, the bore of the highest tsunami wave offshore limited the amount of suspended sediment due to a steep bathymetric profile of the shoreface and a moderate initial drop in water level prior to the arrival of the bore. This resulted in limited suspension and shoreward advection of the sediments and a minor contribution of the seafloor sediments to the onshore tsunami deposit. Visualization of the onshore sediment transport indicated that the sediment transport was significantly affected by artificial topographic features. The flow speed and height varied across the topographic highs, and sediments were trapped on the seaward side of these highs. In coastal areas, the sediment supply was limited due to the presence of engineered dikes along the coast. In inland areas, embankments of paved roadways caused increased deposition on the seaward sides of the embankments and less deposition on the leeward sides of the embankments. Although some aspects of the relevant physics were not fully implemented in the model, in which uncertainties exist, the results may explain the processes and consequences of sedimentation from a tsunami event.
KW - Numerical modeling
KW - Sediment transport
KW - Sendai Plain
KW - Tohoku-oki tsunami
KW - Tsunami deposit
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U2 - 10.1016/j.margeo.2014.05.005
DO - 10.1016/j.margeo.2014.05.005
M3 - Article
AN - SCOPUS:84914100001
VL - 358
SP - 18
EP - 37
JO - Marine Geology
JF - Marine Geology
SN - 0025-3227
ER -