Pacific Ocean closed loop of the andesite line are most of the deep troughs, submerged volcanic mountains, and oceanic volcanic islands that characterize the Pacific basin. Here basaltic lavas gently flow out of rifts to build huge dome-shaped volcanic mountains whose eroded summits form island arcs, chains, and clusters. Outside the andesite line, volcanism is of the explosive type, and 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. The Pacific Ocean is the only ocean which is almost
Alpide belt by ongoing plate tectonics such as the Alpine orogeny. The belt is the result of Mesozoic-to-Cenozoic-to-recent closure of the Tethys Ocean and process of collision between the northward-moving African, Arabian and Indian plates with the Eurasian plate. Indonesia lies between the Pacific Ring of Fire along the northeastern islands adjacent to and including New Guinea and the Alpide belt along the south and west from Sumatra, Java and the Lesser Sunda Islands (Bali, Flores, and Timor). The 2004 Indian Ocean earthquake just off the coast of Sumatra was located within the Alpide belt. Alpide belt The Alpide belt or Alpine-Himalayan