The data base of the cruise consists of 3900 milles of bathymetry, gravimetry and magnetism profiles and 2000 milles of single channel seismic reflection profiles; 31 dredgings were also successfully performed. New Hebrides back-arc troughs are located in the northern and southern part of the rear of the New Hebrides arc. There is no trough in front of the collision/subduction of the d'Entrecasteaux ridge. The objectives of the cruise were to collect more data concerning the structure and the volcanism in this area in order to solve the problem of age and origin of the structures observed at the back of the arc.