Volcanoes form at boundaries where tectonic plates meet underwater or on land. Eruptions occur when magma travels up from the mantle through the crust and vents on the surface, emitting lava, ash, gases or a combination. Different types of volcanoes include shield volcanoes which erupt fluid lava over large areas, cinder cone volcanoes which throw chunks of hardened lava into the air, and composite volcanoes which build up layers of ash and lava. Volcanoes shape the land by emitting new rock and changing landscapes over thousands of years through eruptions.

1. How do volcanoes shape
the land?
Chapter 5: Lesson 3:

2. Openings in earth’s crust.

3. Volcanoes are located on certain places on
earth’s surface.
(Found where tectonic plates meet)

4. A circle of volcanoes (Ring of fire) follows the
boundaries of plates that meet along the pacific
ocean.

5. Eruption
Outpouring of ash, gases, lava or a combination of these.

6. Magma chamber
Inside a volcano
Vent
Vent
Smoke and ashes
Crater
Lava

7. Crater
(cup shaped
depression)

8. Volcanoes erupt where one plate is pushed
under another.

9. The hole that is formed when the chamber
under the volcano is emptied and the volcano
collapses.
Caldera

10. 1) Dike
(Formed when magma hardens in vertical or nearly
vertical cracks)
Underground magma formations

11. 2) Sill
(Formed when magma hardens in horizontal layers of
rock)

12. 3) Laccolith
(A dome shape formed when magma is pushed into a sill
and doesn’t spread)
When a laccolith is formed it may push the layers of rock above it.

13. 4) Batholith
(Huge, irregular shape deep in the earth’s crust)

14. Active volcanoes
(Currently erupting or
recently erupted)
Types of volcanoes
Dormant
volcanoes
(Does not erupt
for some time)
Shield
volcanoes
Cinder-
cone
volcanoes
Composite
volcanoes
Extinct volcanoes
(Stopped
erupting)

15. 1) Shield volcanoes
Built by thinner, fluid lava that spreads over a
large area.
(Broad base and gently sloping sides)

16. 2) Cinder-cone volcanoes
Formed by thick lava that is thrown high up in the
air and fall as chunks or cinders.
(Form as cone shape with narrow base and steep sides)

17. 3) Composite volcanoes
Built by layers of ash and cinders sandwiched
between layers of hardened lava.
(Both sides of a composite volcano look the same)

18. Active volcano not on
boundary

19. Hot spot
(A stationary pool of magma)
The Hawaiian islands are
form an island chain.
The origin of the
Hawaiian island
volcanoes is the hot
spot.

21. Island arc
(Formed in areas where an ocean floor
plate is pushed under another ocean floor
plate.)