First Permanent U.S. Deep Seafloor Observatory Installed
Scientists and engineers funded by the National Science Foundation (NSF) and affiliated with the Incorporated Research Institutions for Seismology (IRIS), the University of Hawaii and the Woods Hole Oceanographic Institution (WHOI) have successfully created the first permanent deep ocean seafloor observatory in the United States. The observatory will be able to observe ocean processes over periods of years.
By connecting a junction box to a retired telephone cable on the seafloor in the middle of the Pacific Ocean between Hawaii and California, the observatory is placed in 5.0 kilometers (16,400 feet) of water almost halfway between Hawaii and California. The facility rests on a relatively featureless part of the seafloor between the Murray and Molokai Fracture Zones.
"As oceanography continues to evolve from an exploratory endeavor, requiring long-term, multi-parameter measurements, the ability to make observations of ocean processes over periods of years is becoming increasingly important," says Larry Clark, program director in NSF's division of ocean sciences, which funded the project. "Recent technological advances and the 'retirement' of seafloor telecommunications cables have enabled the establishment of seafloor observatories that are connected to shore by a dedicated cable. The ability to continuously receive and record oceanographic data and communicate with scientific instruments on the seafloor promises to advance ocean science knowledge and predictive capabilities."
Named the Hawaii-2 Observatory, or H2O, the project was coordinated through the Incorporated Research Institutions for Seismology (IRIS) in Washington, D.C., under the direction of Rhett Butler, global seismic network program manager. In addition, scientist Fred Duennebier at the University of Hawaii designed the power supply and built a seismic instrumentation package that attaches to the junction box, which was designed and built at WHOI. A seismometer and a standard hydrophone are the first instruments to be installed at the site. Now that power is flowing through the cable, the instruments will immediately begin listening for seismic events such as earthquakes and tsunamis.
"It was a risky operation, but something we have wanted to do for a very long time," notes scientist Alan Chave of WHOI. "Up to now we have been limited by technology and logistics in supporting a permanent undersea geophysical observatory. Now we have the technology -- with the remotely operated vehicle Jason, the titanium junction box, and the cable providing the power and communications source to link us back to shore. The two-way digital signals carried by the cable are unique in that they allow us to 'talk to' our instruments on the seafloor, so that we can program and troubleshoot them from land."
The unique junction box and cable termination of titanium were installed by splicing into the middle of the submarine telephone cable connected to AT&T's Makaha cable station on the island of Oahu.
In the future, scientists from universities and research laboratories around the world will be able to plug instruments into the junction box (with the help of a submersible or ROV), then unplug the instrument when their experiment is complete.
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