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
McDonald Islands (volcano) of satellite imagery noted that an eruption took place on 12 July 2005 on the northwest shore of the island. The eruption may have added a small portion to the area of the island. In 2002 the Heard Island and McDonald Islands were declared a marine reserve; this was expanded in 2014. The islands are also recognised as a World Heritage Site. McDonald Islands (volcano) The McDonald Islands () are the peaks of a volcano in the southern Indian Ocean in the vicinity of Heard Island (). The islands are Australian external territory. Prior to 1992, the volcano had not