vent or fissure in the earth's crust (or in the surface of some other planet) through which molten lava and gases erupt.
Where does volcanic activity occur?
In 3 main areas of plates: 1. Spreading ridges undersea and on continents (Divergent boundaries, new crust produced) 2. Subduction zones (Convergent boundaries, old crust destroyed) 3. Hot Spots within plates