1. Volcanoes How they change the surface of Earth!

2. Before eruptionAfter Eruption Mt. Saint Helens A volcano is a weak spot in the crust where magma is expelled. 2 Boundaries: divergent & convergent.

3. Side by side photo to compare before and after the eruption on May 18, 1980

4. 2 Types of Eruptions: Explosive: More rare than non explosive More destructive than non- destructive Blows molten rock into the air Produces mostly pyroclastic material

5. AAPahoehoe Not all Volcanos are so explosive and destructive… Quiet Volcanos (non-explosive):  Most Common  Produced by calm flows of lava

6. Kilauea has been erupting since 1983!! While it can be explosive at times, it is usually just a constant flow.

7. Many times the lava flows into the Pacific Ocean and cools to create new land.

8. Where are more then half of all the active volcanos on Earth located? THE RING OF FIRE surrounding the PACIFIC PLATE.

9. Hawaii is not located close to a plate boundary. So how can it have so many volcanoes?? It is located over a HOTSPOT!

10. So What is inside of the volcano? Magma chamber: is a body of molten rock underground Vent: cracks on the Earth’s surface

12. Silica and Magma The more silica that magma contains, the more explosive the eruption. Pyroclastic material: what forms when magma is blasted into the air and hardens.

13. Eruptions and Climate Change As volcanic ash and gases spread through the atmosphere, they can block enough sun to cause global temperatures to drop!

14. Shield Volcano Cinder Cone Volcano 3 Types of Volcanoes Composite Volcano

15. Shield: forms from quiet eruptions, creates a wide- based, gently sloping mountain Cinder cone: explosive eruptions, tall, narrow mountain, and formed from pyroclastic material Composite: formed from alternating quiet and explosive eruptions. Also called a Stratovolcano!

16. Crater Lake Landforms Created: Craters-funnel shaped pits near the top of a central vent

17. Other landforms created: Calderas- large semi-circular depression that forms when magma chamber below has been emptied Lava Plateau-a landform caused by repeated eruptions of lava spread over a large, flat area.

19. Active: smoking, active volcano; lava, smoke coming out or very soon Dormant: sleeping volcano. Nothing happening but could. Extinct: dead volcano, unlikely to erupt again

20. Where in our universe is the largest volcano??? Answer: MARS Olympus Mons It is 3 times bigger then Mt. Everest and it is a shield volcano!