Y. Kaneda¹ , K. Kawaguchi²

¹Kagawa University, Kagawa, Japan
²Japan Agency for Marine-Earth Science and Technology (JAMSEC), Kagawa, Japan

Abstract:

The Dense Ocean-floor Network system for Earthquakes and Tsunamis (DONET) is the first real-time seafloor observatory network monitoring earthquakes and tsunamis at high-accuracy, high-density, and large-scale in the seismogenic zone. It consists of various geophysical sensors such as seismometers and pressure sensors connected by submarine cable. DONET uses state-of-the-art technologies in order to achieve a sustainable seafloor observatory network, for which three functional components are employed: a “high reliable backbone cable system”, a “maintainable science node”, and an “expandable observatory”. To assemble these components, modular architecture has been designed in contrast to the conventional in-line linear seafloor network. Hybrid wet-mate connectors are used between each component, which allows us to do easy maintenance of the observatory by remotely operated vehicle (ROV). A science node, which plays an important role as a hub-to-spoke function, can also make it possible to increase/separate observatory flexibly. The first DONET was deployed in 2010 followed by the second DONET in 2016. 51 observatories are now in operation in DONET, and their data availability rate has been kept at more than 90 % since the deployment. Success of DONET development can contribute to the new generation seafloor observatory for future deployment in the world’s oceans.