Regional Scale Nodes (RSN) Survey Report Prepared for The University of Washington FINAL HYDROGRAPHIC S URVEY REPORT FOR THE REGIONAL SCALE NODES (RSN) COMPONENT OF THE OCEAN OBSERVATORIES INITIATIVE (OOI) PREPARED FOR: REGIONAL SCALE NODES PROGRAM OFFICE 909 NE BOAT STREET SEATTLE, WA 98105-6671 TEL: 206-543-5064 JANUARY 14, 2011 PREPARED BY: L-3 COMMUNICATIONS MARIPRO, INC. WILLIAMSON & ASSOCIATES 1522 COOK PLACE 1124 NW 53RD ST. GOLETA, CA 93117 SEATTLE WA, 98107 TEL: (805) 967-0367 TEL: (206) 285-8273 Prepared by L3 MariPro i Regional Scale Nodes (RSN) Survey Report Prepared for The University of Washington EXECUTIVE SUMMARY The fiber optic cable network of the Regional Scale Nodes (RSN) component of the Ocean Observatories Initiative (OOI) is composed of eight segments located off the coast of central Oregon. The configuration of the cable routes is as follows: • Segment 1: Pacific City Oregon to Primary Node PN1A • Segment 2: Primary Node PN1A to Primary Node PN1B • Segment 3: Primary Node PN1B to Primary Node PN1C • Segment 4: Primary Node PN1C to Primary Node PN1D • Segment 4NP: Primary Node PN1D to Low Voltage Node LV01D • Segment 5: Pacific City Oregon to Primary Node PN5A • Segment 6: Primary Node PN5A to Primary Node PN3A • Segment 7: Primary Node PN3A to Primary Node PN3B The following briefly summarizes the findings of the survey interpretation on a segment by segment basis: Segment 1 • Segment 1 water depths range from 0 m at the landfall to 2920 m at Primary Node PN1A, with slopes on the lower continental slope as high as 22.5° in the survey corridor. • Seabed sediments in the surveyed area range from soft, unconsolidated sand, silt and clay to bedrock. • Shelf features include sand/gravel waves, a sand dollar patch, pockmarks, bottom contact fishing scars. • Slope features include areas of exposed bedrock and strata, mini-basins in-filled with thick sediment deposits, steep slopes, faults, gas features, and buried mud diapirs. • Five side scan sonar contacts are logged for this segment, none of them closer than 160 meters from the survey route. • The route crosses the active VSNL Pacific SEG G5 cable twice, but both crossing are in deep water and cross at angles greater than 45 degrees. • 25 CPTs, 15 gravity cores, and 6 grab samples were taken. CPTs achieved 0.17 to 3.03 meters penetration and gravity cores ranged from 0.28 to 4.7 meters penetration. • 3 areas of concern were identified that may need special consideration with respect to cable burial. Segment 2 • Segment 2 water depths range from 2920 m at Primary Node PN1A to 1230 m at Primary Node PN1B, with slopes on the lower continental slope as high as 45.9° in the survey corridor. • The route does not cross any existing cables. • Seabed sediments in the surveyed area range from soft, unconsolidated silt and clay to bedrock. Prepared by L3 MariPro i Regional Scale Nodes (RSN) Survey Report Prepared for The University of Washington • Geologic features include areas of exposed bedrock and strata, authigenic carbonate (carbonate crust on the seabed), and gas-related features. • No sonar contacts were found. • 2 CPTs and 1 gravity core were taken. All CPTs penetrated to 3.0 meters and the gravity core penetrated to 1.58 meters. • No areas of specific concern were identified. Segment 3 • Segment 3 water depths range from 1310 m just south of Primary Node PN1B to 616 m at Primary Node PN1C, with slopes as high as 3.1° in the survey corridor. • The route does not cross any existing cables. • Seabed sediments in the surveyed area range from unconsolidated silt and clay to older, presumably harder outcropping strata. • Bottom contact fishing scars were noted. • Geologic features include areas of exposed strata, authigenic carbonate, and gas- related features. • One sonar contact was found approximately 2 km north of the Primary Node PN1B. • 5 CPTs and 2 gravity cores were taken. All CPTs and gravity cores achieved 3 meters or better penetration. • No areas of specific concern were identified. Segment 4 • Segment 4 water depths range from 620 m south of Primary Node PN1C to 112 m at Primary Node PN1D, with slopes as high as 5.2° in the survey corridor. • Seabed sediments in the surveyed area range from soft, unconsolidated sand, silt, clay and gravel to strata of variable hardness and bedrock. • Bottom contact fishing scars were noted. • The route does not cross any existing cables. • Geologic features include faults, turbidity channeling, authigenic carbonate, pockmarks, a relict slump deposit and gas-related features. • 19 CPTs and 12 gravity cores were taken. All CPTs penetrated to 3 meters and gravity cores penetration varied from 0.52 to 3 meters. • No sonar contacts were found. • 2 areas of concern were identified. One of these areas is a concern for burial while the other is a concern for events that could compromise the cable during the system’s life. Segment 4NP • Segment 4NP water depths range from 112 m at Primary Node PN1D to 79.5 m at Low Voltage Node LV01D, with slopes as high as 3.7% (2.1°). Prepared by L3 MariPro ii Regional Scale Nodes (RSN) Survey Report Prepared for The University of Washington • Seabed sediments in the surveyed area are sand with possible gravel in the floors of channels. • The route does not cross any existing cables. • Bottom contact fishing scars were not noted. • Geologic features include structurally deformed seabed (ridge-troughs) and minor channeling. • Two sonar contacts were found. The closest of these contacts come within 74 meters of the route. • 4 CPTs and 3 gravity cores were taken. The CPTs penetrated from 0.3 to 3.0 meters and the gravity cores had no recovery or penetration to 0.3 meters. • There are no areas of concern, but the slopes along the edges of the ridge-trough features may present challenges for the plow if crossed directly. Segment 5 • Segment 5 water depths range from 0 m at the landfall to 2825 m in the Cascadia Channel, with slopes on the lower continental slope as high as 26.6° in the survey corridor. • Seabed sediments in the surveyed area range from soft, unconsolidated sand, silt and clay to bedrock. • The route crosses 3 active existing fibre-optic cables (VSNL Pacific Seg G5, Southern Cross Seg F, PC 1 Seg E). All crossings occur in deep water and cross at angles greater than 70 degrees. • Shelf features include sand/gravel waves, a sand dollar patch, pockmarks and bottom contact fishing scars. • Slope features include areas of exposed bedrock and strata, mini-basins filled with thick sediment deposits, steep slopes, faults, gas features, and mud diapirs. • Six side scan sonar contacts are logged for this segment. One of these contacts lies within 103 meters of the survey route. • 25 CPTs, 9 gravity cores, and 6 grab samples were taken. The CPTs had refusal as shallow as 0.36 meters and penetration to 3 meters, the gravity cores penetration was from ‘No recovery’ to 3 meters. • 1 area of concern was identified that may need special consideration with respect to cable burial. Segment 6 • Segment 6 water depths range from 2615 to 2875 m with slopes as high as 2.8° in the survey corridor. • The route crosses 1 active fibre-optic cables (AKORN Seg 2-2), One Out-of-Service fibre-optic cable (TPC-4), 2 out of service telegraph cables (Bamfield-Fanning Is , and Bamfield-Fanning Is-1) and one out of service coax cable (Compaq Seg 2). All of these crossing are and an angle of 26° or greater. • No areas of concern are identified for this route. Prepared by L3 MariPro iii Regional Scale Nodes (RSN) Survey Report Prepared for The University of Washington Segment 7 • Segment 7 water depths range from 1515 to 2630 m with slopes as high as 15.8° in the survey corridor. • The route does not cross any existing cables. • Since one goal of the RSN project is to monitor the active Axial Volcano, it goes without saying that this segment is in jeopardy from volcanic eruption. Beyond this potential hazard, there are no identified areas of concern for this route. • The cable installer should be made that the terrain in this area is highly irregular, but the slopes do not exceed 18.8% (10.6°) along the route. Prepared by L3 MariPro iv Regional Scale Nodes (RSN) Survey Report Prepared for The University of Washington Issue and Approval Control Sheet Copies of this Report have been distributed as follows: 0 Williamson and Associates 1 1 L-3 Communications MariPro 3 2 University of Washington 1 The following versions of this report have been issued: Rev No. Date File Name Description 1 6/20/2010 RSN Survey Report_1 6-20-10 Preliminary Report 2 10/12/2010 Final RSN Survey Report_2 10-12-10 Final Survey Report 3 10/13/2010 Final RSN Survey Report_2 10-13-10 Final Survey Report 4 1/?/2010 Final RSN Survey Report_3 1-?-11 Final Survey Report Approval: Approved for Issue: ________________________ Date: _________ Patrick Harwell Hydrographic Survey Coordinator L3-MariPro Prepared by L3 MariPro v Regional Scale Nodes (RSN) Survey Report Prepared for The University of Washington ABBREVIATIONS AND ACRONYMS AoC Area of Concern KM Kilometer BMH Beach Manhole KTS Knots CPT Cone Penetrometer Test LP Landing Point CTD Conductivity-Temperature-Depth M Meter DEM Digital Elevation Model Ma Mega-annum (1 million years) DGPS Differential Global Positioning System Mb Geologic Member (of a formation) DPR Daily Progress Report MBES Multibeam Echo Sounder DTS Desktop Study MCPT Mini Cone Penetrometer Test EEZ Exclusive Economic Zone MLLW Mean Lower Low Water EFH Essential Fish Habitat MMS Minerals Management Service EOB End of Burial