About 70 percent of the world's earthquakes and about 75 percent of the world's active volcanoes (some469volcanoes) occur along the ring of fire (figs.1and13a).Shaped like a,40,000-kilometer horseshoe,the volcanoes and the earthquakes stretch from the southern tip of South America,up along the coast of North America,along the Alaska-Japan -Philippine trench,and connect to the Tonga-Kermadec trench and then to the Hikurangi trench to the south in New Zealand (fig.13).