Austral Islands

The Austral Islands are the southernmost archipelago of French Polynesia, a chain of seven volcanic islands in the South Pacific covering about 152 square kilometers. They were built by a hotspot beneath the still-active Macdonald seamount, which rises to within 40 meters of the surface some 338 kilometers southeast of the chain, and the islands show a clear age progression as the Pacific Plate has moved over that hotspot, from about 28.6 million years old in the northwest to just 3.3 million years old in the southeast. The chain is grouped into the Tupua'i Islands in the northwest and the Bass Islands in the southeast, with Mont Perau on Tupua'i reaching the highest point at 650 meters. About 6,965 people lived across the islands' five municipalities as of 2017, with Tupua'i serving as the administrative capital.