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USGS Coastal and Marine Geology Program

Field Activity Details for field activity D196NC

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AKA: none

Other ID: D-1-96-NC

Status: Completed

Organization(s): USGS, Pacific Coastal and Marine Science Center, National Oceanic and Atmospheric Administration

Funding Program(s):

Principal Investigator(s): Kim Klitgord, Rob Zierenberg

Affiliate Investigator(s): Bob Embley (NOAA)

Information Specialist(s):

Data Type(s): Location-Elevation: Navigation, Sampling: Geology, Seismics: Air Gun / Water Gun, Sonar: Sidescan

Scientific Purpose/Goals:

Vehicle(s):

Start Port/Location: Seattle, WA

End Port/Location: Seattle, WA

Start Date: 1996-07-08

End Date: 1996-08-07

Equipment Used: airgun, gravitycore, GPS, sidescansonar

Information to be Derived:

Summary of Activity and Data Gathered:

Staff: Michael Boyle, Kaye Kinoshita, Larry Kooker, Jane Reid, Stephanie Ross, Stuart Sides, Miguel Velasco

Affiliate Staff:
Bill Chadwick (NOAA) - Navigation and Geologist
Julia Getsiv (NOAA) - Navigation

Notes: Leased SSS from Western Region Marine and Coastal Surveys Bulletin, July 26, 1996... Good eating (and results) on the Disco Jane reid sends news from National Oceanic and Atmospheric Administration (NOAA)s research vessel Discoverer (aka Disco), where she, Kim Klitgord (co-chief scientist), and about half a dozen other USGSers are cooperating with NOAA in a three-week cruise off the pacific northwest. They are collecting sidescan-sonar and seismic-reflection data in three areas: (1) the coaxial segment of the Juan de Fuca Ridge, where a volcanic eruption occurred in 1993; (2) the northern part of the Gorda Ridge, where a volcanic eruption occurred in april of this year; and (3) Escanaba Trough (southern Gorda Ridge), where hydrothermal vents and a thick blanket of sediment have produced large sulfide deposits analogous to deposits on land.. here is the report Jane sent last week: "After some initial problems (non-sinking transponders, sticky winch, and overly hot sidescan system) we are now getting great sidescan and sub-bottom profiles over NOAAs floc area of the coaxial segment of the Juan de Fuca Ridge. The transponder net is well calibrated and the winch is working to fly the towfish at altitudes of about 160 meters above the bottom. The data looks wonderful: fault scarps and fissures and lava structures from recent flows. sidescan images are coming in clear and sharp. Acoustic navigation is intermittent, but Stuart Sides and Miguel Velasco from Flagstaff have kept up with the processing and we expect to have a completed mosaic in the next week or so. After a couple of short deployments and recoveries on the southern part of the Juan de Fuca, its off to Escanaba Trough for 8 days of side-scan work and seismic lines. The weather has been swell, though we expect it to get sweller (a low is headed our way). The food is excellent. expect some waddling when we return. What we all need are fewer Haagen Daz bars and more Altoids." for more information about vents in the northeast Pacific (and links to pages about other neat stuff) check out this NOAA page on the world wide web: http://www.pmel.noaa.gov/vents/ from Western Region Marine and Coastal Surveys Bulletin, August 2, 1996... More news from the Discoverer The Escanaba part of the survey is collecting great data right now. We have two excellent NW and two NE trending profiles across the mounds region and are about to start the third. Great records on the sidescan, 4.5khz, and airgun systems. the quality is definitely above expectations. Poor fish nav but good ship nav. 25-30 knot winds have delayed us a bit due to difficulty holding courses going with the wind, so we have had to make some adjustments to acquire the desired data. Still the prospects for 100% data of the trough, but unless there are major problems we will have not trouble acquiring all of the primary data in the mounds vicinity. Seismic data indicate that we may be able to develop a relative fault age distribution. Rob Zierenberg is thrilled with sidescan images over the mounds with 1000m swaths at 100m above seafloor. Sulfide mound zones are clearly visible. NW trending faults coming into the mounds are "very" linear. could not ask for better images. Very easy to correlate faults and other structures in the airgun data with features on the deep towed sidescan and 4.5khz data. sidescan processing is nearly complete for the NOAA Juan de Fuca co-axial region study and Stuart and Miguel are already working on the Escanaba data. Larry, Mike, and Tom have a superb seismic reflection profile record coming in. Initial processing of seismic reflection data is already underway on Tommys Silicon Graphics machine, for both airgun and 4.5khz data sets. Swath bathymetric processing for escanaba is about to start but should be easy by comparison with the Juan de Fuca data set. Operations are smooth and the whole team is putting in a great effort. The Williamson team is providing great support.:Kim Discoverers good voyage The Disco is coming into port today, ending the last oceanographic cruise of her 30-year career. If all goes as predicted, she "will be escorted in by a fire boat, spraying water as we approach the locks into lake union. Were stopping in Everett to pick up 80 or 100 crew dependents so they can transit the rest of the way in. We should arrive at the dock on Lake Union about 1:30 p.m. on Friday. whee!" Jane Reid Heres a recap on the cruise from Kim Klitgord. The NOAA-USGS cruise on the NOAAs Discoverer, with Robert Embley (NOAA) and Kim Klitgord (USGS) as co-chief scientists, has successfully completed its sidescan sonar studies of the co-axial segment of the Juan de Fuca Ridge (NOAA vents program) and the Escanaba Trough on the southern Gorda Ridge. The AMS-60 sidescan sonar system and 4.5 khz sub-bottom profiler system leased and operated by Williamson and associates were used for both surveys. At Escanaba Trough, nearly 350 km of near-bottom sidescan sonar and 4.5 khz sub-bottom penetration data and surface towed airgun seismic reflection data were acquired on a grid of 18 lines over the Nesca hydrothermal system within the axial valley of Escanaba Trough. A tight grid of 1 to 2 km spacing swaths in both the NNW and NE directions have provided two complete sidescan mosaics with different image angles for interpreting the surficial geologic character of the 18 km x 25 km region centered on the hydrothermal mounds that are the drill target for the ODP leg 169 that starts later this month with Rob Zierenberg (USGS) as co- chief scientist. Stuart Sides and Miguel Velasco (Flagstaff) have already completed the sidescan sonar processing and Rob is hopping from the Discoverer to the Joides Resolution with a set of fantastic mosaics. The 4.5 khz seismic system routinely imaged over 50 meters below the seafloor and provided a superb stratigraphic record of the interlinked volcanism, deformation and turbidite deposition within Escanaba Trough. "z"

Location:

Gorda Ridge

Boundaries
North: 41.17267 South: 40.3945 West: -127.853 East: -127.36833

Platform(s):

photo of Discoverer
Discoverer

Publications

Ross, S.L., and Zierenberg, R.A., 2009, Sidescan sonar imagery of the Escanaba Trough, southern Gorda Ridge, offshore northern California: U.S. Geological Survey Scientific Investigations Map 2907, 125 p., http://pubs.usgs.gov/sim/2907/.

Portals/Viewers

Data Acquired

Survey EquipmentSurvey InfoData Type(s)Data Collected
airgun --- Air Gun / Water Gun
gravitycore --- Geology
GPS --- Navigation
Global positioning system (GPS) data d-1-96-nc.060 (Provisional best file)
lines
sidescansonar --- Sidescan
sidescan (data on FAD)

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