Multi-disciplinary VENUS observation at the Ryukyu Trench using Guam-Okinawa geophysical submarine cable

Development of Japanese scientific cable technology

“…The reuse of decommissioned telecom-cables has been attempted since 1990's by many researchers to reduce the cost of deployment for real-time marine observations [3] [11] [12]. The experience showed that the cost could be minimized if and only if any reuse projects are conducted in a well prepared way by a well organized implementation structure of researchers.…”

“…So-called multi-sensor experiments were conducted using the same underwater connection technologies [3]. Since 1990, the development of scientific cabled observation technologies could be characterized by the introduction of fiber-optic signal transmission and of underwater mateable connectors.…”

Development of integrated marine monitoring network on southern coastline of Caspian sea

“…Technical guidelines for the design of various components such as measuring devices, the location of monitoring buoys, and the data gathering intervals for each of the hydrodynamic and seawater-quality parameters also were introduced. These have been periodically updated based on the results of gathered data and have been applied for prediction of marine environmental conditions such as storms, violent waves and seawater-level variations (Kasahara et al, 2006;Davies et al, 2001;Vassallo et al, 2008). In Europe, marine monitoring design codes were developed in consideration of special seawater-quality criteria (Iannaccone et al, 2009;Jonge et al, 2006).…”

A New Multidisciplinary Marine Monitoring System for the Surveillance of Volcanic and Seismic Areas

“…This has allowed investigations of geophysical processes at both global and regional scales in the Pacific Ocean and the European margin, under different programs from the United States, Canada, Japan, and the European Community (see Delaney et al 2000;Stutzmann et al 2001;Shirasaki et al 2003;and Romanowicz et al 2006; for a review, see also . Japan was the first country to work on the extension of its geophysical monitoring to the ocean floor (Kasahara et al 2006), and now has eight cabled seafloor observatories operating to date within the framework of the ARENA (Advanced Real-time Earth Monitoring Network in the Area) project. At the present feasibility study stage, ARENA is designed to deploy a mesh-like network of underwater cables that connects both terrestrial and underwater observatories all around the Japanese archipelago (Massion et al 2004).…”

“…In spite of this, in many of the most seismically hazardous and highly populated areas (e.g., off Chile, Mexico, and in Mediterranean countries such as Portugal, Italy, Greece, and Turkey), geohazard monitoring systems still remain exclusively land-based, with seafloor data generally acquired only on a temporary basis during episodic periods. The major causes that at present limit the extensive implementation of seafloor networks for geohazard monitoring relate to the need for the huge investment of funds, high management costs, and the technical and logistical difficulties involved in the deployment and maintenance of monitoring systems on the seafloor (Kasahara et al 2006). For instance, the logistical elements-including ships, submersible vehicles, and specialized teams of operators-are too expensive for a single research institution, and assembling them thus demands cooperative efforts and cost sharing.…”