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USGS Coastal and Marine Geology Program

Field Activity Details for field activity Z106SC

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AKA: none

Other ID: Z-1-06-SC

Status: Completed

Organization(s): USGS, Pacific Coastal and Marine Science Center

Funding Program(s):

Principal Investigator(s):

Affiliate Investigator(s): David Caress, Charlie Paull

Information Specialist(s): Bill Normark

Data Type(s): Location-Elevation: Navigation, Seismics: Boomer, Sonar: Multibeam

Scientific Purpose/Goals: Five AUV dive days were planned in Santa Monica Basin offshore Los Angeles, CA. The primary targets were a mud volcano from which methane hydrate was cored in 2003 (see USGS cruise A-1-03-SC) and giant scour depressions (2 km wide) had been imaged on USGS multibeam data in the upper reach of the Redondo fan valley. The areas mapped are in water depths of 650 to 850 m. The primary MBARI objective of these dives was to determine the shallow structure and shape of the mud volcano. In addition, the USGS project interests were to determine the form and sedimentary structure of the fan valley floor in the area of the giant scours. Both of the these target areas had been photographed and sampled using the MBARI ROV Tiburon during cruise W-1-05-SC.

Vehicle(s):

Start Port/Location: Moss Landing, CA

End Port/Location: Moss Landing, CA

Start Date: 2006-06-04

End Date: 2006-06-10

Equipment Used: GPS, Chirp, multibeam

Information to be Derived: Very high-resolution bathymetry and subbottom structure in the deeper part of Santa Monica Basin. Bathymetric maps are produced at a one-meter contour interval.

Summary of Activity and Data Gathered: 1200/JD155 R/V Zephyr departs Moss Landing. ~1500/JD156 Begin first AUV dive on outer shelf in Santa Monica Bay ~0100/JD161 Complete final AUV Dive near ODP Site 1015 ~0600/JD162 R/V Zephyr arrives in Moss Landing A total of 5 AUV dives were completed. Each dive was initiated on the outer shelf edge in Santa Monica Bay so that the AUVs starting position could be determined by GPS at the launch site. The vehicle then drives to the pre-planned survey site by tracking the sea floor with the Doppler sonar log. The AUV can survey with the multibeam sounding system and chirp sonar for about 8 to 9 hours; it then returns to the sea surface to be picked by the R/V Zephyr. The expedition consisted of two separate operations and separate scientific parties. The R/V Zephyr would launch the AUV in early morning and then wait to retrieve the vehicle after it finished mapping. The R/V Zephyr would then dock at Marina del Rey around early evening where the data would be transferred to a server in a temporary field office established in an apartment adjacent to the marina. The second scientific party would then process the data until about 0100, at which time the trackline for the next survey would be set and prepared to load into the AUV. All primary objectives of the cruise were attained.

Staff: Bill Normark

Affiliate Staff:
Charlie Paull
David Caress
Bill Ussler
Rendy Keaton
Duane Thompson
Doug Conlin
Hans Thomas
Paul Ban
Aaron Gregg
Matt Noyes

Notes: MBARIs automated underwater vehicle (AUV) for sea-floor mapping. The AUV has a high-resolution Edgetech chirp sonar profiling system and a mult ibeam sounding system and uses both Doppler sonar tracking of the sea floor and an inertial guidance system for position control. The AUV surveys are conducted about 60 m above the sea floor.

Staff information imported from InfoBank
Charlie Paull
David Caress
Bill Ussler
Rendy Keaton
Bill Normark
Duane Thompson
Doug Conlin
Hans Thomas
Paul Ban
Aaron Gregg
Matt Noyes

Location:

southern Santa Monica Basin

Boundaries
North: 33.86089 South: 33.71375 West: -118.822 East: -118.5333

Platform(s):

photo of Zephyr
Zephyr

Publications

Portals/Viewers

Data Acquired

Survey EquipmentSurvey InfoData Type(s)Data Collected
GPS --- Navigation
Best file with nav in ArcInfo E00 format
Global positioning system (GPS) data (Provisional best file)
Chirp --- Boomer
multibeam --- Multibeam

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