On 11 August, 2009, at 05:07 JST, a moderate-to-large earthquake struck two deep ocean water pipes, which reach 397 m and 687 m deep at Suruga Bay in the near-field. We carried out two surveys by using R/V Natsushima and ROV Hyper-Dolphin for better understanding of damage of the water pipes and its cause. The first survey was done by using ROV Hyper-Dolphin, which contained the visual surveys. We have realized that the 687 m water pipe has been flowed at least 2 km away from the original laid position. The second survey using R/V Natsushima was done in order to reproduce the bathymetry map in the source area. We could discover an erosion pattern created near the 687 m water pipe, whereas a sediment pattern in the downstream, which is possibly a submarine landslide evidence caused by the earthquake.
