1. Volcanoes

2. Volcano: Opening in the earth through which lava flows and the material that builds up on the surface around the opening.

3. Magma vs. Lava Magma: Liquid rock inside the earth

4. Lava: Magma that erupts onto the earth’s surface

5. What causes a volcano to erupt? Hot, liquid rock is less dense than solid rock so it rises

6. As more rock melts it expands upwards and melts more solid rock along the way

7. Eventually it forces through cracks in the surface

8. Where do volcanoes occur? Subduction Zones

9. Mid-ocean ridges

10. Hot spots: volcanoes in middle of a plate New volcanoes form as plate moves past hot spot

12. Types of Volcanoes Shield Volcano: Broad at the base with gently sloping sides, quiet eruptions

15. Cinder Cones: Made when solid fragments called pyroclasts are ejected from volcano, violent eruptions Very steep sides Only a few hundred meters high

18. Composite/Stratovolcanoes: Made up of alternating quiet and explosive eruptions Makes layers of different hardened rock Best known of all volcano types Ex: Mt. Fuji, Mt. Rainier, Mt. Hood, Mt. Shasta, and Mt. St. Helens

27. 1980

28. 2005