Kuwae, Submarine volcano in Vanuatu.

Kuwae is a submarine volcano in Vanuatu that forms a caldera stretching between the islands of Epi and Tongoa. The caldera reaches 12 kilometers in length and 6 kilometers in width and lies entirely below the ocean surface.

The fifteenth-century eruption buried much of Tongoa and Epi under pyroclastic flow deposits, and pumice fall reached Tongariki. Carbonised trunks killed by the flows date to 1410–1450 CE, while bone collagen from Ti Tongoa Liseiriki, the survivor of Tongoan tradition, gives 1475±85 CE. Whether the Kuwae caldera between Epi and Tongoa formed in this eruption, or a caldera south of Tongoa did, remains debated.

People on Tongoa pass down the story of Ti Tongoa Liseiriki, who fled to Tongariki during the eruption and survived. This oral tradition moves from one generation to the next and connects the islanders to the event.

The water above the caldera turns discolored regularly due to volcanic activity beneath the surface. Vessels therefore keep a safe distance from the zone and avoid crossing directly through the affected area.

Between 1897 and 1901 eruptions created a temporary island that was one kilometer long. The newly formed land eroded completely within six months and disappeared again beneath the waves.