- Two plates collide or separate
- Magma rises from the mantle to the vent
- This is called an eruption
- Magma wells from the magma chamber and reaches the surface where it cools and hardens.
- This is known as lava.
- After many eruptions, layers of lava and ash build up around the vent.
- As a result, a cone-shaped mountain is formed with a crater on top from which the lava flows.