CIRCE Expedition is primarily a deep-sea geological-geophysical cruise, similar in scientific program to S.I.O.'s MONSOON (1960–61), LUSIAD (1962–63), and DODO (1964) Expeditions to the Indian Ocean. The aim is to investigate bottom topography (by precise sounding and photography), magnetic patterns, heat-flow, sediment thicknesses in basins and on shelves, hardrock distribution and type, chemical properties of sediments and the overlying water, and variation in the earth's magnetic field near the magnetic equator.