Other ID: STRL S7-87-AFR
Organization(s): USGS, Woods Hole Coastal and Marine Science Center
Principal Investigator(s): George R. Driscoll
Information Specialist(s): George R. Driscoll
Data Type(s): Electro-Magnetic: Gravity, Sonar: Single Beam, Electro-Magnetic: Magnetics, Location-Elevation: Navigation
Scientific Purpose/Goals: Collect gravity, magnetics and bathymetric data off the west coast of Africa on a 5 nmi grid with an internal consistency of +/- 3 milligals.
Start Port/Location: Abidjan, Cote d'Ivoire
End Port/Location: Douala, Cameroon
Start Date: 1987-09-24
End Date: 1987-10-20
Equipment Used: GPS (wh), 12 kHz, LaCoste-Romberg gravimeter G-179, Geometrics G-856 magnetometer, Gyro compass, GE 810 Correlation sonar
Information to be Derived:
Summary of Activity and Data Gathered: Departed Abidjan, Ivory Coast on 24 Sep. On 25 Sep., resurveyed 2 Ghana lines due to high cross checks. On 26 Sep., surveyed 1 Togo line and 1 Benin line and started Nigeria survey. On 5 Oct., completed Nigeria and began Cameroon survey. On 8 Oct., completed Cameroon survey and began Gabon survey. 18 Oct., transit to Douala. 20 Oct., arrived Douala, Cameroon for crew change and provisions. The 810 Sonar/MK 29 Gyro system worked flawlessly as did gravimeters and all gravity processing equipment and software. Many lines had to be cut short on the eastern end due to shoals, or shifted due to restricted oil platform areas.
Staff: Nancy K. Soderberg, Catherine Delorey, George R. Driscoll
Robert Bowles - consultant; Larry Awosika - Nigerian Institute of Oceanography & Marine Research; Lt. A.G. Inusa - Nigerian Navy Hydrography Office; Tomah Jabez Nhabay - Geological Survey
Project = Defense Mapping Agency Gravity, Defense Mapping Agency Gravity
Ghana, Togo, Benin, Nigeria, Cameroon, Gabon, Equatorial Guinea, Africa, North Atlantic, South Atlantic;
|North: 7||South: 3||West: 1||East: 8|
Folger, D.W., McCullough, James R., Irwin, Barry J., Driscoll, George R., Delorey, Catherine M., and Polloni, Christopher F., 1990, Map showing free-air gravity anomalies off the western coast of Africa; Nigeria to Gabon: U.S. Geological Survey Miscellaneous Field Studies Map MF-2098-F, scale 1:1,500,000.
|Survey Equipment||Survey Info||Data Type(s)||Data Collected|
|LaCoste-Romberg gravimeter G-179||---||Gravity|
|12 kHz||---||Single Beam||1987-040-FA-SE-001 ( Collection of paper record displays of seismic data (12 kHz) for lines )|
|Geometrics G-856 magnetometer||---||Magnetics|
|GE 810 Correlation sonar||---||Navigation|