Optimization of Pore Pressure Observation in a New Borehole Off the KII Channel: Toward High-Precision Extraction of Crustal Deformation Components

In January 2024, JAMSTEC operated real-time monitoring of pore pressure and fiber optical strain sensor in a new borehole off Kii Channel to monitor seismic activity and seafloor crustal deformation around the source region of Nankai earthquake. This paper will provide a brief review of our observatories along the Nankai Trough. Since the initial conditions have been reduced and the instrumental drift component has stabilized due to sufficient elapsed time, we will also present the crustal deformation extracted from the pore pressure data, discussing the influence of ocean disturbance as a noise factor and the stress impact on the seafloor pressure, which is thought to affect the generation cycle of slow slip events