The South African Geodynamic Observatory Sutherland (SAGOS) of GFZ was established during the years 1998 – 2000 based on an Agreement on Cooperative Activities between the National Research Foundation (NRF) and GFZ, signed in August 1998. SAGOS is located at the site of the South African Astronomical Observatory (SAAO). The operation and maintenance of the SAGOS instrumentation is jointly done by staff of SAAO and GFZ.
The SAGOS observatory is located about 350 km north-east of Cape Town (longitude: 20.81 E, latitude: 32.38 S, altitude: 1755 m). The shortest distance to the South Atlantic coastline is about 200 kilometres. The area is located in a tectonically quiet zone far away from the African rift. Geologically, the setting is a huge dolerite plateau with a several kilometres thick layer of dolerite. This bedrock allows a good coupling of the Superconducting gravimeter (SG) pillars to the ground. The environment is a remote area with no industry and low seismicity. The climate at this place is determined by the border between summer and winter rainfall zones so that temperature fluctuations are not too rough. The observatory is also built into the ground to protect it against environmental effects like strong winds and temperature changes. All rooms are thermally insulated. An air condition system controls the temperature inside the measurement chamber, which is equipped with three concrete pillars embedded into the dolerite bedrock. Two of the pillars are constructed for Superconducting gravimeters or other geophysical instruments. The third pillar is dedicated for absolute gravimeters for the calibration of the Superconducting gravimeters. In the vicinity of the observatory four further pillars were set up for various other geodetic antennas and instrumentation.
SAGOS is a high precision geodynamic observatory comprising space techniques and ground instruments. Presently the observatory is equipped with