Download Volcanoes - Verona Public Schools

I. What is a Volcano?

A volcano is any opening in the Earth’s
crust where magma, ash and gas are able
to reach the surface

Volcanoes may have more than one
opening which are called vents

The main vent is known as the crater
I. What is a Volcano?

Far below the crater is the magma
chamber

Magma rises from the magma chamber,
through a conduit, into the throat of the
volcano, until it reaches the crater
1. Large Magma Chamber
2. Bedrock
3. Conduit (pipe)
4. Base
5. Sill
6. Dike
7. Layers of Ash Emitted by the
Volcano
8. Flank
9. Layers of lava emitted by the
Volcano
10. Throat
11. Parasitic Cone
12. Lava Flow
13. Vent
14. Crater
15. Ash Cloud
II. What Causes Volcanoes?

Volcanoes are caused by one of three things:
1. Convergent tectonic plates, usually at a
continental-oceanic plate subduction zone
2. Divergent tectonic plates, usually at a
mid-oceanic ridge
3. Mantle plumes a.k.a. “hot spots”
III. Three Major Types of Volcanoes
1. Shield Volcano
•
Broad with gentle slope similar to a shield
•
Produced by low-viscosity lava flows
•
Mild eruptions
•
More common in oceanic than continental
settings
Mauna Kea in Hawaii
III. Three Major Types of Volcanoes
2. CompositeVolcano (Stratovolcano)
•
Tall with steeper slopes similar to a cone
•
Produced by high-viscosity lava flows
•
Explosive eruptions of alternating layers
of ash, cinders and lava
•
More common in subduction zones
Mount Fuji in Japan
Mount Mayon in Phillipines
III. Three Major Types of Volcanoes
3. Cinder Cone
•
Small with steepest slopes
•
Produced by explosive lava flows
•
Violent eruptions
•
Commonly found around shield or
composite volcanoes
Sunset Crater in Arizona
Capulin Volcano in New Mexico