Trials of seafloor geodetic monitoring around Japan

Institute of Industrial Science, University of Tokyo and the Hydrographic and Oceanographic Department, Japan Coast Guard have been constructing a seafloor geodetic observation network around Japan in order to detect and monitor the crustal deformation of the seafloor directly. The observation network had been constructed along the major trenches, such as the Japan trench and the Nankai trough. Observations to measure the positions of the seafloor stations have been conducted repeatedly. Sufficient observational results have been established as we accumulate the experience of the observations to discus the system and the observational method. Although we reached certain level with the existing system, we come up with possible improvements of the system. Trials to improve the system are always done in order to achieve a fully centimeter level geodesy on the seafloor.