Kuwae was a landmass that existed in the vicinity of Tongoa and was destroyed by volcanic eruption in fifteenth century, probably through caldera subsidence. The exact location of the caldera is debated. A submarine caldera, now known as Kuwae caldera that is located between the Epi and Tongoa islands, is a potential candidate. Kuwae caldera cuts through the flank of the Tavani Ruru volcano on Epi and the northwestern end of Tongoa. Another potential candidate is a proposed caldera between Tongoa and Tongariki.