1. Volcanoes

2. What is a volcano?
 A volcano is basically anywhere on the crust where magma comes to the surface

3. Where are volcanoes found?
 Volcanoes are found in two typical locations:
◦ Near plate boundaries
◦ At hot spots – an area where magma from the mantle melts through the crust above it. (Hawaiian Islands)
 Ring of Fire – volcanoes around the Pacific Ocean

4. Earth’s Active Volcanoes

5. How does a volcano erupt?
PRESSURE!!!
 Magma rises to the surface
 Gases dissolved in the magma
rush out, carrying the magma with them (like a shaken bottle of soda)

7. How are volcanoes classified?
There are 3 different types of
volcanoes, each one is based on
how they were formed:
◦ Shield volcanoes
◦ Cinder cone volcanoes
◦ Composite volcanoes or Stratovolcanoes

11. Different types of eruptions
Quiet – mostly lava Pyroclastic (explosive) –mostly ash, cinders, bombs, and gases

12. What makes an eruption quiet or explosive?
Magma is mostly made of silica (silicon + oxygen = silica)
 The more silica in the magma/lava, the thicker it is.
 The thicker it is, the more explosive the eruption.

13. Different types of lava flow
There are two types of lava flow:
◦ AA – a thick, slow moving lava flow (like mashed potatoes)
◦ Pahoehoe – a thin, fast-moving lava flow (like gravy)