Geology of the Pacific Ocean Guinea, and New Zealand lie outside the andesite line. Outside of the andesite line, volcanism is explosive; the Pacific Ring of Fire is the world's foremost belt of explosive volcanism. The Ring of Fire is named after the several hundred active volcanoes that sit above the various subduction zones. In 2009, the deepest undersea eruption ever recorded occurred at the West Mata submarine volcano, a mile beneath the ocean, close to the Tonga-Kermadec Trench, within the Ring of Fire; it was filmed by the US Jason robotic submersible which descended over . The Pacific Ocean is the only ocean which
Geography of the Philippines of mountain ranges in this region is called "Zamboanga Cordilleras", with the highest elevation at Mount Dapi, which is high. The southern coastline is irregular, featuring two smaller peninsulas, the Sibuguey and Baganian, extending southward to the Moro Gulf. To the north of the Diwata Mountains at northeast Mindanao lie Siargao island and the Dinagat group of islands. Southwest of the Zamboanga Peninsula is the Sulu Archipelago, a chain of islands which comprise the smaller archipelago provinces of Basilan, Sulu, and Tawi-Tawi. The Philippines is divided into a hierarchy of local government units (LGUs) with the 81 provinces and 38