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
Battle of the Komandorski Islands Battle of the Komandorski Islands The Battle of the Komandorski Islands was a naval battle between American and Imperial Japanese forces which took place on 27 March 1943 in the North Pacific, south of the Soviet Komandorski Islands. The battle was a daylight surface engagement in which air support played a negligible role and in which the inferior American force escaped complete destruction mostly by luck. When the United States became aware of Japanese plans to send a supply convoy to their forces on the Aleutian Islands of Alaska, U.S. Navy ships commanded by Rear Admiral Charles McMorris were sent