The Izu–Bonin–Mariana (IBM) arc system is a tectonic plate convergent boundary in Micronesia. The IBM arc system extends over 2800 km south from Tokyo, Japan, to beyond Guam, and includes the Izu Islands, the Bonin Islands, and the Mariana Islands; much more of the IBM arc system is submerged below sealevel. The IBM arc system lies along the eastern margin of the Philippine Sea Plate in the Western Pacific Ocean. It is the site of the deepest gash in Earth's solid surface, the Challenger Deep in the Mariana Trench.
Cross-section through the shallow part of a subduction zone showing the relative positions of an active magmatic arc and back-arc basin, such as the southern part of the Izu–Bonin–Mariana Arc.
Simplified tectonic history of the IBM arc system, viewed along E-W profiles. Red corresponds to regions of magmatic activity, blue is magmatically extinct.
Simplified bathymetric and topographic profile along the IBM magmatic arc
The Izu Islands are a group of volcanic islands stretching south and east from the Izu Peninsula of Honshū, Japan. Administratively, they form two towns and six villages; all part of Tokyo Prefecture. The largest is Izu Ōshima, usually called simply Ōshima.
Shikinejima from Kōzushima. Furthest: Ōshima; left: Toshima; right: Niijima; smallest: Jinai-tō.
Oshima Airport.
Image: Hachijojima tamaishigaki 2007 03 20
Image: Niijima Habushi Beach
