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 created a brief reign of terror on Car Nicobar as they rounded up forced labour amongst the Nicobarese. The occupation left a legacy of lasting bitterness towards the Japanese, and to some extent towards their collaborators in the "Arzi-Hukumat-e Azad Hind", amongst the generation which experienced it. Japanese Vice Admiral Hara Teizo, and Major-General Tamenori Sato surrendered the islands to Brigadier J A Salomons, commander of 116th Indian Infantry Brigade, and Chief Administrator Mr Noel K Patterson, Indian Civil Service, on 7 October 1945, in a ceremony performed on the Gymkhana Ground, Port Blair. Japanese occupation of the Andaman Islands