Assignment for Science - 2013

1. Volcanoes
By Le Vinh

2. Contents
• Introduction
• Types of volcanoes
• Types of volcanic eruptions
• Where can you find volcanoes
• Why volcanoes erupt
• What drives these volcanoes
• What does a mountain need to count as a volcano
• Diagram of a volcano
• Impacts on people when a volcano erupts

3. Introduction
• Volcanoes are a mountain that bursts with lava. Some are
active, some are dormant, and some are extinct
• Active volcanoes can erupt any time
• Dormant volcanoes have not erupted for many years but an
eruption is still possible
• Extinct volcanoes are rather, eroded/worn away by old
structures turning brittle, completely destroyed, or have their
magma chambers completely solidified

4. Types of volcanoes
Complex Volcano
Shield Volcano
Stratovolcano
Cinder Cone
Lava Dome
Supervolcano

5. Shield Volcano
• Shield volcanoes have a semicircular shape which is
basically formed by viscous lava turning into layers of the
gentle sloped volcano. It is known for its shield like
structure and low profile

6. Complex volcano
• Complex volcanoes are volcanoes with multiple vents or
explosion craters which overlap each other and pour lava
which flows from the cone to the whole volcano

7. Stratovolcano
• Stratovolcanoes are the most common type of volcano
than any other volcano, and the most dangerous volcano
type, human evolution has ever witnessed

8. Cinder cone
• Cinder cones are the smallest volcano type in the planet,
standing less than 1,000ft. They blast lava fragments in
mid air then toss them down

9. Lava Dome
• Lava domes are inflated piles of molten rock or magma
that rises to the surface and cools, Some are volcanoes
with craggy cliffs gently curving and some are hot domes
with trapped gasses

10. Supervolcano
• Supervolcanoes are the most terrifying volcanoes on
Earth, They may be outnumbered but their never
outmatched

11. Types of eruptions
Hawaiian
Strombolian
Plinian Fissure

12. Hawaiian
• Hawiian eruptions are gentle lava flows which goes to
the bottom of the volcano

13. Fissure
• Fissure eruptions erupt in a line form flooding with loads
of hot lava

14. Plinian
• Plinian eruptions form a mushroom cloud raining with
burning rock and thick ash sheets

15. Strombolian
• Strombolian eruptions throw lava bombs hundreds of
meters into the air and spew out sticky lava

16. Where can you find
volcanoes
• Volcanoes are found in geothermal zones or
uninhabitable places or near a fault line. They can be
found in a hotspot region surrounded by water. They can
be part of a volcano group like the Cascade Volcanic
Range which stretches out from California to Washington
or the Aleutian Volcanic Arc which stretches out from
Alaska Peninsula to Kamchatka Peninsula that are
merged to form the Pacific Ring Of Fire which surrounds
the rim of the Pacific Ocean

17. Why Volcanoes erupt
• Volcanoes erupt because of two factors. One is that
magma that is less dense than the rock surrounding it
tries to float to the surface. The magma contains
dissolved gases and water from tectonic movement. The
volcano pushes the magma towards the surface and
when the magma reaches the surface, the dissolved
gases and water will now expand into steam and gas
causing a huge eruption
• Two is that the magma increases in volume and the
magma that’s lighter is pushed towards the bottom of the
crater. The lighter magma reaches the rim of the crater
and is now lava and overflows

18. What drives these
volcanoes?
• Volcanoes are either driven by tectonic activity which swirls
magma to form volcanoes. Then the magma pushes all the way
to the Earths surface, bursting lava upwards to form the volcano.
There are hundreds of submarine volcanoes which are in a
volcanic group like the Hawaiian volcanic ridge or the Mid
Atlantic Volcanic Ridge. These submarine volcanoes were able
to burst lava upwards but stopped growing before the cone went
above sea level.

19. What does a mountain
need to count as a volcano
• Volcanoes are not the same as those that are formed in
landmass collisions. Yet they need requirements to count
as a volcano
1: It needs to spill lava, molten rock and ash
2: Its base needs to be round although fissure vents are line shaped
3: It needs to be separate from other mountains although some
mountains have extra vents or close to other mountains
4: It needs to have a magma chamber underneath to support it
5: It needs to be constructed out of a type of ash, lava, molten rock

20. Diagram of a volcano
• Here’s my attempt of making a volcano diagram
Magma
chamber
Ash Deposit Layers
Crater
Extra vent (if possible)
Central Vent
Conduit

21. Affects on people when
a volcano erupts
• Volcanoes affect people in either good or bad, The good
thing about the affects of volcanoes is it can produce
rich soils for crop growing and farming and the bad thing
about its affect is that it can consume houses. Luckily, it
is too slow to run over people

22. Resources
• http://en.wikipedia.org/wiki/Main_Page
http://volcano.oregonstate.edu/how-do-
volcanoes-affect-people
http://www.universetoday.com/77111/why-
do-volcanoes-erupt
/

23. Conclusion
• Thanks for watching this
presentation and I hope you
enjoyed it