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
History of the Marshall Islands islands in 1944, destroying or isolating the Japanese garrisons. In just one month in 1944, Americans captured Kwajalein Atoll, Majuro and Enewetak, and, in the next two months, the rest of the Marshall Islands, except for Wotje, Mili, Maloelap and Jaluit. The battle in the Marshall Islands caused irreparable damage, especially on Japanese bases. During the American bombing, the islands' population suffered from lack of food and various injuries. Of the 5100-man Japanese garrison (2600 Imperial Japanese Navy and 2500 Imperial Japanese Army) on the Mili Atoll only half survived to the end of the war. Following capture and occupation