Disclaimer: All data are subject to revision without notice; exact locations of mooring sites are not yet finalized; exact depths of sensors will be determined at the time of deployment.
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The RSN provides unprecedented power (10 kV, 8 kW) and bandwidth (10 GbE) to scientific sensor arrays on the seafloor and throughout the water column using moorings with instrumented wire-following profilers, 200 m instrumented platforms, and winched profilers. A shore station in Pacific City, Oregon includes two cable landings serving key sites on the RSN: Hydrate Ridge, Axial Seamount, and the Endurance Array – Oregon Line. The ~ 900 km of modified telecommunications cable (installed in 2012) provides power and bandwidth to seven Primary Nodes: PN1A (Base Slope at the base of the Cascadia margin west of Newport, OR); PN1B (Southern Hydrate Ridge); PN3A (Base of Axial Seamount), PN3B (Axial Seamount Eastern Summit); and PN5A (Mid-Plate); and Hydrate Ridge segments to nodes PN1C and PN1D, which comprise part of the Coastal Scale Nodes (CGN) Endurance Oregon Line extension. Primary Node 1C is shared by RSN and CGN. The Primary Nodes convert the high power voltage (10 kV) of the primary cable to a lower (375 V) level and distribute it to Science Ports along with communications and timing signals. A 5-km cable will extend from the mid-plate site that is currently not equipped for science, but allows for future expansion.
As the first U.S. ocean observatory to span a tectonic plate, this facility will provide a constant stream of data in real-time from throughout the water column and from the seafloor associated with the Juan de Fuca plate. With a vertical dimension provided by a network of instrumented cabled moorings at five initial sites, the RSN and shared Endurance Array will enable interdisciplinary observations of water-column processes offshore of the continental margin in a region strongly forced by air-sea interaction, by shelf-slope interactions with the deep sea, and by coupled atmospheric/oceanic phenomena acting to produce variations in North Pacific circulation over gyre scales.
Other key instrumented focus sites on the RSN include Southern Hydrate Ridge and Axial Seamount. Southern Hydrate Ridge is an important observatory site to define the temporal evolution of methane hydrate systems in response to seismic events, to determine material fluxes from the seafloor and impacts on overlying ocean chemistry, and to understand biogeochemical coupling associated with gas-hydrate formation and destruction. The seeps host novel chemosynthetic biological communities that utilize methane in their metabolic processes. As an initial start to instrumenting the Cascadia subduction zone and Juan de Fuca plate, the RSN will be installing a small array of seismometers at the base of the accretionary margin west of Hydrate Ridge (PN1A) and at the summit of Southern Hydrate Ridge.
Over 70% of global volcanism occurs along mid-ocean ridge spreading centers, yet no long-term observations of these systems have yet been made. Mid-ocean ridge processes are inherently episodic on decadal timescales and are also short-lived. The RSN focuses on Axial Seamount because it is the most magmatically robust volcano on the spreading center, having erupted in 1998 and most recently in April 2011. It hosts numerous active hydrothermal fields (e.g., Ashes and the International District) and abundant sites of diffuse flow. It is the only site where in situ pressure sensors have documented up to 15 cm/year inflation prior to an eruption. It is also the only site where there are extensive time-series measurements documenting the evolution of microbial communities following submarine volcanic eruptions. Myriad cabled sensors will be installed at the summit of Axial Seamount to monitor major volcanic and tectonic events that create the oceanic crust and that modulate heat, chemical, and biological fluxes through the seafloor. Axial is also an important site to study the emission of carbon dioxide and other gases into the water column during and following volcanic events.
Axial Seamount 46°N, 130°W
Hydrate Ridge 45°N, 125°W
Axial Seamount 1516 to 2654 m
Hydrate Ridge 807 to 2909 m
- A land-based Shore Station in Pacific City, Oregon
- ~ 900 km of high power (8kW) and high bandwidth (10 GbE) modified telecommunications cable
- Seven subsea terminals called Primary Nodes to distribute power from the Shore Station to key sites along the Juan de Fuca Plate
- 17 Medium-Power and Low-Power Junction Boxes (J-Box)
- 3 cabled water column sites (PN1A, PN1C and PN3A) each hosting two instrumented moorings (a deep profiling mooring from 3000 m to ~ 200 m and a shallow profiling mooring, hosting a platform at 200 m and a winched profiler from 200 m to near sea surface). One mooring (PN1C) is shared with the Endurance Oregon Line
- 111 water column and seafloor sensors focused near the base of each mooring and at Southern Hydrate Ridge and Axial Seamount
- 119 km of extension cables providing power and communications to secondary infrastructure and sensors
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For more information on RSN Infrastructure click here.
For more detailed tables on the Slope Base Mooring click here.
For more detailed tables on the Hydrate Ridge click here.
For more detailed tables on the Axial Seamount click here.
Click here to download a PDF of all Regional Scale Node Infrastructure Tables.
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