The big wave suddenly invaded to the beach, and three children were carried off to the sea by the wave though they played on the beach. The beach characteristic topography has the cusp topography and steep slope. This study tried to comprehend the reason why this accident occurred. Firstly, this study comprehended the wave condition when the accident occurred. Secondary, this study made the survey about the geographic feature of the beach. And this study obtained the geographic data for the numerical simulation from the aerial photograph which were taken by Drone. Finally, this study comprehended the wave dynamics on the beach by the numerical simulation. This study simulated the wave dynamics by the horizontal two dimensional numerical model and the vertical two dimensional numerical model.
The accident that three children and two adult males who tried to rescue the children died occurred at Jogehama beach Japan in 2014 (see Fig.1). The wave run up to 28m from the shoreline when the accident occurred. The beach was known in the around area for the small cusp topography and steep slope. Therefore, the beach was the swimming prohibited area, and they played on the beach when the accident occurred. However, the big wave suddenly run up to the beach, and the children were swept out to sea. Our group reproduced the wave run up condition by the numerical simulation, and compre-hended about the wave run up speed and the water level. This time, we tried to know whether the same phenomenon occurs or not at other coast area in Niigata prefecture.
Firstly, we comprehended the wave condition when the accident occurred. In this case, we used vertical two dimensional model, CADMAS-SURF2D. After comprehending the accident ouucred condition, the wave run up condition was comprehended by changing the wave height and the period. According to the result, when the wave height will be about 1m, adults will fall down in the wave run up area. Secondary, we tried to extract the same beach with Jogehama. As the result, some beachs were extracted. According to the result, we went to the extracted beachs, and comfirmed that the wave run up conditions were same with Jogehama beach.
