“…Further work is needed to understand the causes of such elevated degassing. It is worthy of note that the central arc segment is subjected to both a westward inflow of enriched, possibly sulphur-rich Indian-type MORB mantle ( [Monzier et al, 1997] , [Peate et al, 1997] and [Turner et al, 1999] ) and to the collision with the d'Entrecasteaux ridge since 2-3 Ma ( [Collot et al, 1985] , [Collot et al, 1992] , [Burne et al, 1988] , [Greene and Collot, 1994] , [Taylor et al, 1994] and [Laporte et al, 1998] ) that has led to back-arc shortening ( [Collot et al, 1985] and [Louat and Pelletier, 1989] ) and to the development of tranverse fracture zones which may facilitate magma ascent beneath Ambae and Ambrym ( [Pontoise et al, 1994] , [Baker and Condliffe, 1996] and [Monzier et al, 1997] ).…”