1. Volcanoes
By: Amy Axelrood

2. Formation and Eruptions of Volcanoes
Gas and buoyancy pressure push magma up against the earths crust
Weak parts in the earth’s crust fracture and crack and the magma erupts out
Eruptions can be violent and explosive or non-explosive

3. Types of Volcanoes There are four types of volcanoes Shield Volcano
Cinder Cone Volcano
Composite Volcano
- Lava Domes

4. Shield Volcano Gently sloping Can be some of the largest volcanoes
Is formed when thin layers of lava pour out of a vent and harden on top of previous layers
Its profile looks like a warriors shield
Created the Hawaiian Islands
Mauna Loa

5. Cinder Cone Volcano Steep, cone shaped hill or mountain
Materials build up around the edges to create a cone shape
They have violent and explosive eruptions

6. Composite Volcano Tall, cone shaped mountains
Layers of lava alternating with layers of ash
Some examples are Mt. Fuji (left) and Mt. Saint Helens (next slide)
Wider base than Cinder Cone

7. Mt. Saint Helens Lava Domes
Due to the lava’s thick density and inability to flow the lava clogs the vent
There is still pressure on the lava, but instead of flowing it domes up and hardens

8. Location