GPS/Acoustic seafloor geodetic observation ―Progress by the Japan Coast Guard (review) ―

Abstract

Progress in the GPS/Acoustic seafloor geodetic observation carried out by the Japan Coast Guard during the 5 − year period since 2000 is reviewed, especially focusing on the development of data analysis methods and their results. A precision better than several centimeters has been attained in the seafloor station positioning through tremendous efforts for improving accuracy of component techniques both in software and hardware. A couple of remarkable results have been presented : an intraplate crustal velocity off Miyagi Prefecture caused by the subduction of the Pacific plate and co−seismic displacements associated with large earthquakes having occurred along the Nankai Trough in 2004 and off Miyagi in 2005. Further issues to be tackled in the future are summarized.