NUMERICAL SIMULATION OF DEFORMATION OF SAND BAR FORMED AT TIP OF FUTTSU CUSPATE FORELAND BY THE 2011 TSUNAMI

Akio Kobayashi,Masumi Serizawa,Takaaki Uda,Masatoshi Endo,Shiho Miyahara

doi:10.9753/icce.v34.sediment.18

Akio Kobayashi, Masumi Serizawa + Show 3 more

Open Access

https://doi.org/10.9753/icce.v34.sediment.18

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Abstract

Futtsu Point is a cuspate foreland separating Tokyo Bay and the Uraga Strait. On March 11, 2011, a tsunami generated by the Great East Japan Earthquake entered Tokyo Bay with approximately 2 m height, and flowed over this sand bar, dispersing the sand and leaving an isolated protruding sand bar. This resulted in the seawall at the foot of the sand bar being exposed to waves, increasing the potential for damage. After the tsunami, this isolated sand bar was significantly deformed, a sand spit was formed by the action of wind waves, and the seawall was refilled with sand. The subsequent shoreline changes of this protruding sand bar were measured, and the three-dimensional beach changes were calculated using the BG model (a three-dimensional model for predicting beach changes based on Bagnold’s concept).

Highlights

On March 11, 2011, a tsunami generated by the Great East Japan Earthquake entered Tokyo Bay with approximately 2 m height, and flowed over this sand bar, dispersing the sand and leaving an isolated protruding sand bar
This isolated sand bar was significantly deformed, a sand spit was formed by the action of wind waves, and the seawall was refilled with sand
The most important effect upon the deformation of the sand bar at the tip of Futtsu Point is caused by obliquely incident wind waves

Summary

Introduction

On March 11, 2011, a tsunami generated by the Great East Japan Earthquake entered Tokyo Bay with approximately 2 m height, and flowed over this sand bar, dispersing the sand and leaving an isolated protruding sand bar This resulted in the seawall at the foot of the sand bar being exposed to waves, increasing the potential for damage. The subsequent shoreline changes of this protruding sand bar were measured, and the three-dimensional beach changes were calculated using the BG model (a three-dimensional model for predicting beach changes based on Bagnold’s concept) proposed by Serizawa and Uda (2011), and compared with the measured shoreline changes

Methods

Results

Conclusion