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 air attacks on the Mariana Islands Japanese air attacks on the Mariana Islands During World War II, a series of Japanese air attacks on the Mariana Islands took place between November 1944 and January 1945. These raids targeted United States Army Air Forces (USAAF) bases and sought to disrupt the bombing of Japan by B-29 Superfortress heavy bombers operating from the islands. The Japanese lost 37 aircraft during this operation, but destroyed 11 B-29s and damaged a further 43. Preparations were also made for commando raids on the bases in early and mid-1945 but these did not go ahead. While the attacks on the Mariana Islands