Detection of Seafloor Movement in Subduction Zones Around Japan Using a GNSS-A Seafloor Geodetic Observation System from 2013 to 2016

In Japan, interplate megathrust earthquakes frequently occur in subduction zones where oceanic plates subduct beneath continental plates, and it is important to elucidate the physical mechanism involved in such earthquakes to prevent associated disasters. Crustal movement data provide essential information to understand plate motion and earthquake source processes. We developed a system that combines GNSS measurements and acoustic ranging techniques to detect seafloor crustal movement. This paper reports the acquisition of recent seafloor crustal movements obtained during campaign observations with a survey vessel, from 2013 to 2016.