Explore the Deep Sea

Volcanoes & Vents

Introduction to plate tectonics and hydrothermal vents.

Multilayer planet

The Earth's structure is a bit like an egg:

Cutaway diagram of Earth's crust, mantle, and core

Volcano zones

map of tectonic plates

On Earth, we see volcanoes in places where molten rock from the mantle rises through the crust to erupt at the surface. Most of these places are found in defined zones where the earth's crustal rocks have cracked because they are being pulled apart, pushed together or stretched as tectonic plates move.

Vents: ocean-floor geysers

We often see hot fluids surge out of the earth in areas of volcanic activity. When this happens on land, we call the erupting fluids "geysers" or "hot springs." Hot fluids shoot out of certain places on the seafloor, too. We call these places "hydrothermal vents" — vents for short. The emerging fluid is not only warm or hot, it often contains all sorts of dissolved minerals and sometimes precious metals. Many hydrothermal vents are found at mid-ocean ridges.

Next: plate tectonics