Volcano Types and
Volcanic Eruptions
1. Why Volcanoes Erupt:
• The F of expanding gas builds and pushes
magma through the vent
2. Major Factors in Eruptions:
• a. The amount of
trapped gas
– CO2 and Sulfur
• b. Silica Content
– The more silica, the
more explosive
C. Common Volcano Products
–Ash:
• Fine rock particles, less than 1/10 of
an inch
C. Common Volcano Products
– Bombs/Cinder
• Rock pieces at least 2.5 inches to many feet
C. Common Volcano Products
• Pyroclastic Flow:
– Mix of hot ash, bombs, gas, pumice and glass that
can travel up to 100 miles per hour.
3. Common Volcano Types
• Shield Volcano
– Structure
– Composition
• Layers of built up lava
– Eruption Type
• Quiet
– Lava Type
• Pahoehoe
– Hazards
• Burning land, ash covered
– Example
• Hawaiian Islands
3. Common Volcano Types
• Cinder Cone
– Structure
– Composition
• Layers of ash, cinders and bombs
– Eruption Type
• Explosive
– Lava Type
• Aa
– Hazards
• Deadly gasses, landslides, avalanche, pyroclastic
flow
– Example:
• Paricutin, Mexico
3. Common Volcano Types
• Composite
– Structure
– Composition
• Alternate lava and ash
– Eruption Type
• Alternate Quiet and explosive
– Lava Type
• Pahoehoe and Aa
– Hazards
• Alternate
– Example:
• Mt. St. Helens
4. Volcanic Activity
• a. Common Volcano Locations
Volcanoes per Continent
So
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p
Eu
ia
As
Af
r
An ica
ta
rc
tic
a
ut
h
Au
st
ra
l
i
Am a
N
er
or
ic
th
Am a
er
ica
250
200
150
100
50
0
Australia
South America
North America
Asia
Europe
Africa
Antarctica
b. Volcanic Eruption simulation
• http://discoverykids.com/games/volcanoexplorer/
4. Volcanic Activity
• b. Life Cycle:
– Active
• A volcano likely to erupt soon
– Ex. Mt. Fuji and Mt. St. Helens
– Dormant
• A Volcano that may erupt in the future
– Mt. Hood, Oregon and Mt. Kilimanjaro, Africa
– Extinct:
• A volcano unlikely to erupt (10,000 years)
– Mt. Buninyong, Australia