Vanished islands in Vanuatu: new research and a preliminary geohazard assessment

Abstract

Oral traditions recalling the disappearances of islands in the volcanically and seismically active central part of the Vanuatu archipelago were collected from informants on Ambae, Maewo, Malakula, and Pentecost Islands. Analyses of the details of these traditions and the meanings of the names of the vanished islands suggest that they once existed. Vanished islands off north-west Malakula, named Tolamp and Malveveng, are likely to have subsided abruptly down the slope to the interarc rift marked by the South Aoba Basin. The unnamed vanished island off the western tip of Ambae is likely to have subsided during a volcanic or seismic event. The vanished island named (Vanua) Mamata between Ambae, Maewo, and Pentecost is also likely to have slipped down the flank of the slope to the South Aoba Basin. Island disappearances of this kind are memorable expressions of the geohazards that affect areas like central Vanuatu. The novel approach adopted here is argued to be an important adjunct to more conventional approaches to geohazard assessment in such places.