Let�s now view volcanism in the Pacific Ocean Basin. Long called the Ring of Fire, a large part of this ocean is rimmed by subduction zone volcanoes. Within the basin are also hot spot-type volcanoes such as on Hawaii (see Chapter 5).

Note on Figure 4.5 how easy it is to discern subduction-type volcanoes: they not only form linear and/or arcuate distribution patterns, but they generally have spatially associated prominent submarine trenches. (9) As our eyes travel southwestward from the Aleutian Island arc of Alaska, we encounter the Kamchatka Peninsula of Russia, then the Japanese volcanic arc, and then south to the Tonga and New Zealand systems in the south Pacific Ocean. In the Western Hemisphere starting in North America, we see the Cascade Range, and then the volcanoes of Mexico that trend southeastward through Central America to and including Costa Rica. Finally, the Andes of South America from Colombia to Chile and Argentina contain both active and extinct subduction-type volcanoes.

What can be generalized about the Ring of Fire volcanic arcs? Most volcanic arcs are 50 km to 275 km (31 to 170 mi) wide and 125 km to 250 km (77 to 155 mi) landward of associated trenches. In the eastern Pacific Ocean, the trenches lie 1,300 km to 13,500 km (810 to 8,380 mi) from the East Pacific Rise spreading center. Subduction rates vary from 3.4 to 10.8 cm per year, and the longest volcanic arc is the Peru-Chile at 6,700 km (4,160 mi).

Volcanoes closer to the trench are generally larger, more closely spaced (30 km to 60 km (18 to 37 mi) apart), and are bigger lava-producers compared with more landward volcanoes. Furthermore, volcanoes are aligned parallel to the trend or strike of the subducting plate.

-from Chapter Four: Convergent or Destructive Plate Boundaries