Plate Tectonic Setting
Map of the Earth's tectonic plates. Compare with the image of the general
features of the ocean basins in the Introduction.
Based on a map prepared by the U.S. Geological Survey.
Like continental volcanoes, submarine volcanoes are most common where tectonic plates
move towards or away from each other. In the case of divergent plate
boundaries, where plates are spreading away from each other, the rate of
plate movement plays an important role in determining the type of volcano
that forms and the rate of eruptive activity. Submarine volcanoes at
convergent plate boundaries (subduction zones) are much like their subaerial
("under air" or continental) counterparts except that the weight of the
overlying water modifies their eruption style. Hot spots leave linear
"tracks" of seamounts across the ocean basins and build some of Earth's
largest volcanoes. The following pages look at volcanoes in each type of