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
Japanese occupation of the Andaman Islands the governor of the islands, and had limited involvement with the administration of the territory. During his interrogation after the war Loganathan admitted that he had only had full control over the islands' vestigial education department, as the Japanese had retained control over the police force, and in protest he had refused to accept responsibility for any other areas of Government. He was powerless to prevent the worst Japanese atrocity of the occupation, the Homfreyganj massacre of the 30th January 1944, where 44 Indian civilians were shot by the Japanese on suspicion of spying. Many of them were members of