御蔵島

Mikurajima is a small steep-sided island located between the more well-known Miyakejima and Hachijojima volcanoes. Oyama forms the summit of the basaltic-to-andesitic island, which is surrounded by cliffs and dissected on the southern-to-eastern sides. The sparsely populated island consists of a large stratovolcano with lava domes on the SE side. Several small sea stacks are located immediately offshore. Growth of the stratovolcano took place until about 7,000 years ago, and the latest activity occurred about 6,000 years ago, when explosive eruptions and pyroclastic surges accompanied lava dome growth.