Other ID: STRL S5-87-AFR
Organization(s): USGS, Woods Hole Coastal and Marine Science Center
Location: Senegal, Gambia, Guinea-Bissau, Guinea, Sierra Leone, Africa, North Atlantic;
Principal Investigator(s): Barry Irwin
Data Type(s): Electro-Magnetic: Gravity, Sonar: Single Beam, Electro-Magnetic: Magnetics, Location-Elevation: Navigation
Scientific Purpose/Goals: Collect gravity, magnetics and bathymetric data around Senegal, Gambia, Guinea-Bissau, Guinea, and Sierra Leone to a 3 nm grid with internal consistency +/-3 mgals.
Start Date: 1987-07-22
Start Port/Location: Dakar, Senegal
End Date: 1987-08-20
End Port/Location: Freetown, Sierra Leone
Equipment Used: LaCoste-Romberg gravimeter G-179, 12 kHz, Geometrics G-856 magnetometer, GE 810 Correlation sonar, Gyro compass, GPS (wh), Magnavox satellite positioning system
Information to be Derived:
Summary of Activity and Data Gathered: Departed Dakar at 1920 on 22 Jul. 1987. The ship proceeded south to survops area. After completing the two remaining lines in Senegal, all runable lines in the waters off The Gambia, Guinea-Bissau, Guinea and Sierra Leone were completed. Most of the onshore lines run north of Sierra Leone were shortened due to shoals on the eastern ends. Gravimeter S-26 lost its 200 Hz power supply on 2 Aug. 87. The unit was swapped with the unit in meter S-41, which was then shut down. S-26 remained online for the remainder of the cruise and showed no evidence of data tears. Arrived in Freetown, Sierra Leone at 1230 on 20 Aug. 1987.
Staff: Barry Irwin, Carol A. Ryland, Sarah Griscom
Notes: Original Center People field contained: Barry Irwin - party chief, Robin Bouse, Sarah Griscom, Carol Renaud.
Folger, D.W., McCullough, James R., Irwin, Barry J., Driscoll, George R., and Polloni, Christopher F., 1990, Map showing free-air gravity anomalies off the western coast of Africa; Senegal (south of 15 degrees north latitude) to Sierra Leone: , download PDF.