Courtesy of NEPTUNE Canada
2nd Stop: Barkley Canyon Node area survey
Barkley Canyon is located South East of ODP 889 on the continental slope West of Vancouver Island
Purpose: Run a West to East 10km route survey of the continental slope topography via ROPOS Canada ROV sector scanning sonar. It is important to survey this underwater topography to determine the hardness of the sediment where the fiber-optic cable will be buried. The main cable will be buried in 1meter of sediment from shore to a water depth of 1500 meters, so that local fishermen don't disturb the cable or vice versa. When the main cable reaches a water depth greater than 1500 meters it will no longer need to be buried. Another important reason for the survey is to ensure no obstacles (boulder outcrops etc.) disrupt the path of the skids plowing and burying the back bone main cable of the NEPTUNE 1st stage. Budgeting cable costs can be accurately estimated by the topography of the cable path. Rougher terrain requires thicker gauge cable that is more expensive than smaller gauge cable. Once the main cable is laid and buried it will be ready to host a node connected to a y-shaped spur in the cable at the Barkley Canyon site, where two cables will branch off the node. One of the braches will extend North of the node and another will extend Southeast of the node. Both branches will have an array of instruments as shown in the figure above. In contrast to the ODP 889 site , this site of study has outcrops of methane hydrates which are exposed, which would require different instruments for monitoring them, like the Bremen Crawler (NEPTUNE Canada website & conversation with Project Scientist Brian Bornhold August 2, 2007).
Methane Hydrate from Barkley Canyon courtesy of NOAA NURP