A near real-time buoy telemetry system for observation of marine earthquake/crustal deformation in Japan

Described is a system designed for conducting long-term observations for earthquake/crustal deformation. The observing system is comprised of a combination of borehole sensors set in a deep-drilled borehole in close proximity to a seismogenic zone, along with a network of additional sensors deployed over a greater spatial area to monitor tectonic events. The topology of the seafloor portion of the sensor (observatory) is a hub and spoke network covering a greater spatial area. The sensors are required a substantial amount of power and data bandwidth to monitor this area. While similar observatories have been proposed; linked to shore using submarine cables, this paper explores the use of a buoy-based system called Ocean Net. With this system, data is carried from seafloor to a surface buoy via a fiber optic cable, whereupon it is transmitted on to shore via a high bandwidth (2-Mbps) satellite link. Generators onboard the Ocean Net buoy provides sufficient electricity to power the extensive network of seafloor sensors.