Aogashima

Aogashima lies in the Pacific Ocean about 358 kilometres south of Tokyo and is part of the Izu archipelago. The island is a compact volcanic landform with steep outer cliffs and a caldera within which a smaller cone rises. The Smithsonian Global Volcanism Program describes the island as roughly 2.5 by 3.5 kilometres and identifies its main volcanic form as a stratovolcano with caldera features.

The Smithsonian Global Volcanism Program records a confirmed explosive and effusive eruption lasting from 1780 to 1785, with a Volcanic Explosivity Index of 3. A peer-reviewed geological study reconstructs the Tenmei eruptive sequence: a small ash eruption in 1781, explosive scoria emission and cone building in 1783, intermittent ash fall in 1785, and lava flows into the Ikenosawa crater. The official Tokyo travel guide notes that the island was uninhabited for about fifty years after the large 1785 eruption.

Aogashima is administered as part of Tokyo. The official Tokyo travel guide describes a small resident population and says the island is reached via Hachijojima, by boat or helicopter; both services are subject to practical constraints, including weather for boat travel. The island’s settlement and limited facilities coexist with its rugged volcanic terrain.