- Vanuatu formed along the converging Australian and Pacific Plates. A fractured, volcanic island arc over 1200km long, it has multiple active volcanoes and many other volcanic structures, some with existing heat flows demonstrated by hot springs.
- There are 9# active volcanoes – 7# on land and 2# subsea along the Wadati-Benioff zone. Other locations have surface manifestations associated with some Holocene volcanic activity.
- Midway along the volcanic arc, the D’Entrecasteaux Ridge caused shallow subduction and the development of a slab tear south of the ridge and the segmentation of the Vanuatu arc into the Northern Block, Central Block and Southern Block.
- As a result of this slab tear, magmatism has been demonstrated anomalously close the Vanuatu New Hebrides Trench. An example is the basalt islands of Nguna, Pele and Emau off the northeast coast of Efate and some basalt structures on Efate itself. Residual heat flux due to convection upflows and conduction has led to the presence of shallow hydrothermal reservoirs here.
- Seismic activity is present with ~24# earthquakes of M7 or greater in the past century revealing ongoing tectonic plate movement.
