The 16 x 9 km, shark-tooth-shaped Koro Island, located between Fiji's Viti Levu and Vanua Levu Islands, is part of the volcanic Lomaiviti Islands. A chain of basaltic cinder cones of upper Pleistocene or possibly Holocene age extends from north to south along the crest of the island (Coulson, 1976). With the exception of one location on the west coast where young lava flows reached the sea, the youngest lava flows, erupted from the NNE-SSW-trending cinder cone chain, are confined to the central plateau, where they form a flat, undissected lava field that extends primarily to the east.