Bonin Islands Pacific Plate is subducting under the Philippine Sea Plate, which creates an oceanic trench to the east of the islands: the Bonin Trench. The crust of the Ogasawara Islands was formed by volcanic activity when subduction began 45–50 million years ago, and is composed mostly of an andesitic volcanic rock called boninite, which is rich in magnesium oxide, chromium, and silicon dioxide. The Ogasawara Islands may represent the exposed parts of an ophiolite that has not yet been emplaced on oceanic crust. The rocks of the Volcano Islands are much younger; Iwo Jima is a dormant volcano characterized by rapid
Banks Islands Ureparapara, is Vet Tagde (Vot Tande or Vot Ganai), an extinct volcano that last erupted 3.5 million years ago. The Rowa Islands (or Reef Islands) are a few very small, low islands on a coral atoll. Mota Lava is the largest and highest (411 m) of this eastern chain of islands; off its southern coast, attached by high corals that one can wade through at low tide, is the tiny islet of Ra. Mota, Merig and Merelava complete the southeastern part of the archipelago. The population of the Banks Islands speak fifteen different languages. Several are endangered, being spoken by