Interplate coupling along the Nankai Trough, southwest Japan, inferred from inversion analyses of GPS data: Effects of subducting plate geometry and spacing of hypothetical ocean-bottom GPS stations

► Developing a new inversion source code, we applied it to the Nankai Trough. ► We find belt-like strongly coupled zone off Shikoku in depths from 15 to 20 km. ► We evaluate effects of different geometry models of the PHS plate on the results. ► We investigate how ocean-bottom GPS stations improve accuracy of solutions.