New Scientific Underwater Cable System Tokai-SCANNER for Underwater Geophysical Monitoring Utilizing a Decommissioned Optical Underwater Telecommunication Cable

Asakawa, Kenichi; Yokobiki, Takashi; Goto, Tada-nori; Araki, Eiichiro; Kasaya, Takafumi; Kinoshita, Masataka; Kojima, Junichi

doi:10.1109/joe.2009.2026987

Cited by 5 publications

(4 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Our OBEM system, in particular, has been gathering electro-magnetic data since January 2005, with observations of salient results for the cabled observatory. Making use of these experiences, we have been constructing a new observatory system off the Tokai region [ 13 , 14 ]. For analyses to yield more precise results, we plan to improve the observatory system further.…”

Section: Discussionmentioning

confidence: 99%

Trial of Multidisciplinary Observation at an Expandable Sub-Marine Cabled Station “Off-Hatsushima Island Observatory” in Sagami Bay, Japan

Kasaya

Mitsuzawa

Goto

et al. 2009

Sensors

View full text Add to dashboard Cite

Sagami Bay is an active tectonic area in Japan. In 1993, a real-time deep sea floor observatory was deployed at 1,175 m depth about 7 km off Hatsushima Island, Sagami Bay to monitor seismic activities and other geophysical phenomena. Video cameras monitored biological activities associated with tectonic activities. The observation system was renovated completely in 2000. An ocean bottom electromagnetic meter (OBEM), an ocean bottom differential pressure gauge (DPG) system, and an ocean bottom gravity meter (OBG) were installed January 2005; operations began in February of that year. An earthquake (M5.4) in April 2006, generated a submarine landslide that reached the Hatsushima Observatory, moving some sensors. The video camera took movies of mudflows; OBEM and other sensors detected distinctive changes occurring with the mudflow. Although the DPG and OBG were recovered in January 2008, the OBEM continues to obtain data.

show abstract

Section: Discussionmentioning

confidence: 99%

Trial of Multidisciplinary Observation at an Expandable Sub-Marine Cabled Station “Off-Hatsushima Island Observatory” in Sagami Bay, Japan

Kasaya

Mitsuzawa

Goto

et al. 2009

Sensors

View full text Add to dashboard Cite

show abstract

“…The AE approach makes use of acoustic detection technology, which is less impacted by external electromagnetic noise and becomes an ideal non‐invasive field detection method [76–78]. The absorption of acoustic waves by insulation materials rises when the frequency increases.…”

Section: Online Monitoring and Defect Detection Methodsmentioning

confidence: 99%

“…The AE approach makes use of acoustic detection technology, which is less impacted by external electromagnetic noise and becomes an ideal non-invasive field detection method [76][77][78].…”

Section: Acoustic Emission Measurementmentioning

confidence: 99%

Review of condition monitoring and defect inspection methods for composited cable terminals

Cao

et al. 2023

High Voltage

View full text Add to dashboard Cite

Composited cable terminals are critical for reliable power delivery of traditional and traction power supply systems. During its operation, the cable terminal continually undergoes complex circumstances where humidity, temperature, field strength, mechanical stress and other factors continuously change at different levels. In extreme cases, defects or even failures may occur in the cable terminals, leading to catastrophic accidents. This makes the condition monitoring and defect detection of composited cable terminals become an imperative need for the power industry. The “state‐of‐the‐art” technology of cable terminal condition assessment is focussed and a systematic review of the current research progress of cable terminal condition assessment from the operation circumstances to failure mechanisms is provided. It covers both online/offline condition monitoring methods and defects detection approaches. In addition, challenges and future research directions for cable terminal condition assessment are also addressed. It is concluded that the non‐destructive and non‐intrusive methods like terahertz imaging and ultrasonic testing, and multi‐source information fusion methods as well as the digital twin technology have been gaining popularity for cable terminal defect inspection. It is expected the presented work can provide a global field of vision for further advancement of both scholars and industrial engineers in this field.

show abstract

“…Kasaya et al (2009) detected precursory electric potential changes associated with seismically generated turbidity flows by connecting electro-magnetometers and pressure gauges to cables laid off Hatsushima. Goto et al (2007) connected an electro-magnetometer to an intelligent node (Asakawa et al, 2009) of a cabled observatory system off Toyohashi city. They attempted continuous resistivity monitoring by current transmission.…”

Section: Introductionmentioning

confidence: 99%

Deep-Sea DC Resistivity and Self-Potential Monitoring System for Environmental Evaluation With Hydrothermal Deposit Mining

2021

View full text Add to dashboard Cite

Environmental impact assessment has become an important issue for deep-sea resource mining. The International Seabed Authority has recently developed recommendations for guidelines on environmental assessment of resource mining effects. Several research and development groups have been organized to develop methods for environmental assessment of the seafloor and sub-seafloor under the “Zipangu in the Ocean program,” a part of the Cross-ministerial Strategic Innovation Promotion Program managed by the Cabinet Office of the Japanese government. One attempt planned for long-term environment and sub-seafloor structure monitoring uses a cabled observatory system. To support this observatory plan, we began development of a system to monitor the sub-seafloor resistivity and self-potential reflecting the physicochemical properties of ore deposits and the existence of hydrothermal fluid. The system, which mainly comprises an electro-magnetometer and an electrical transmitter, detects spatio-temporal changes in subseafloor resistivity and in self-potential. Because of the project’s policy changes, cabled observatory system development was canceled. Therefore, we tried to conduct an experimental observation using only a current transmitter and a voltmeter unit. Data obtained during three and a half months show only slight overall apparent resistivity variation: as small as 0.005 Ω-m peak-to-peak. The electrode pair closest to the hydrothermal mound shows exceptionally large electric field variation, with a semidiurnal period related to tidal variation. Results indicate difficulty of explaining electric field variation by seawater mass migration around the hydrothermal mound. One possibility is the streaming potential, i.e., fluid flow below the seafloor, in response to tides. However, we have not been able to perform rigorous quantitative analysis, and further investigation is required to examine whether this mechanism is effective. The system we have developed has proven to be capable of stable data acquisition, which will allow for long-term monitoring including industrial applications.

show abstract

New Scientific Underwater Cable System Tokai-SCANNER for Underwater Geophysical Monitoring Utilizing a Decommissioned Optical Underwater Telecommunication Cable

Cited by 5 publications

References 13 publications

Trial of Multidisciplinary Observation at an Expandable Sub-Marine Cabled Station “Off-Hatsushima Island Observatory” in Sagami Bay, Japan

Trial of Multidisciplinary Observation at an Expandable Sub-Marine Cabled Station “Off-Hatsushima Island Observatory” in Sagami Bay, Japan

Review of condition monitoring and defect inspection methods for composited cable terminals

Deep-Sea DC Resistivity and Self-Potential Monitoring System for Environmental Evaluation With Hydrothermal Deposit Mining

Contact Info

Product

Resources

About