In 1995, a joint French‐Japanese cruise (ManusFlux) explored the Manus Spreading Center and some sites of the South Eastern Rift in the Manus Basin off the coast of Papua New Guinea (Figure 1) with the Japanese submersible [Auzende et al., 1996; Gamo et al., 1997]. In the framework of this joint project, called New STARMER, the French and Japanese teams completed the Manaute cruise with the R/V LAtalante and the Ifremer submersible Nautile in April and May 2000.

The Manaute cruise explored and sampled volcanic and hydrothermal sites in the eastern part of Manus Basin and on the spreading axis of the Western Ridge (WR). The eastern part of the Manus Basin (Figure 2) was interpreted as a stretched‐back arc basin crust showing alternatively elongated ridges and isolated volcanoes where accretion and hydrothermal activity are distributed [Martinez and Taylor, 1996; Binns et al., 1993].