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
Shield volcano contains at least 43 major volcanoes, and Meiji Seamount at its terminus near the Kuril–Kamchatka Trench is 85 million years old. The volcanoes follow a distinct evolutionary pattern of growth and death. The chain includes the second largest volcano on Earth, Mauna Loa, which stands above sea level and reaches a further below the waterline and into the crust, approximately of rock. Kīlauea, meanwhile, is one of the most active volcanoes on Earth, with the current ongoing eruption having begun in January 1983. The Galápagos Islands are an isolated set of volcanoes, consisting of shield volcanoes and lava plateaus, located