The Parts of a
Volcano
Today’s Journey
• 0507.7.1 Create a model to illustrate geologic events
responsible for changes in the earth’s crust.
• 0507.7.2 Prepare a chart to compare how volcanoes,
earthquakes, faulting, and plate movements affect the
earth’s surface features.
• State Performance Indicators
• SPI 0507.7.1
Describe internal forces such as
volcanoes, earthquakes, faulting, and plate movements that
are responsible for the earth’s major geological features
such as mountains, valleys, etc.
What is a Volcano?
 A volcano is a
mountain that
forms when
magma reaches
the surface of
the Earth.
 Magma rises
because it is less
dense than the
solid rock
around it.
What are the parts of a
Volcano?
1. VENT- the vent is
the opening from
which lava flows.
Dust, ash, and
rock particles can
also be thrown out
of the vent!
2. Crater-
the top of
the volcano. It
is a funnel
shaped pit. It is
formed when
the material
explodes out of
the vent!
3.
Volcanic coneis the pile of
lava, dust,
ashes, and rock
around the vent.
It can be found
in different
shapes!
Types of Volcanoes
• There are 3 types of
Volcanoes:
Shield
Cinder Cone
Composite
• They are
classified by
how they form.
Shield Volcano
• Is wide and somewhat flat.
• It forms from a quiet
eruption.
• Lava flows out quietly and
for great distances.
• Made from divergent
boundaries.
• Divergent boundaries are
places where two of Earth’s
plates move apart. Shield
volcanoes generally form at
divergent boundaries, such
as an ocean floor spreading
center. Shield volcanoes
generally have a smooth,
broad, low shape with gentle
sloping sides.
Hotspots
• Hotspots are unusually hot areas beneath a
plate, where narrow plumes of magma rise
from Earth’s mantle (asthenosphere) to the
surface.
• Shield volcanoes often form at hotspots.
Composite
Volcano
 “Strato” volcano
 Form from explosive
eruptions.
 Produce a lot of lava and ash.
 Is small, with steep sides.
 Form at subductive
(convergent) boundaries.
 Convergent boundaries are
places where two of Earth’s
plates crash together.
Composite or “strato”
volcanoes form at convergent
boundaries. Composite
volcanoes have rugged, steep
sides and are made up of layers
of lava and ash.
Cinder Cone Volcano
 Has tall, very steep sides.
 Has explosive eruptions.
 This eruption produces a lot
of cinder and ash.
 Cinder cone volcanoes can
occur at both types:
Subductive(convergent) and
divergent boundaries!
20.2 Where you find volcanoes
• About half of the
active surface
volcanoes on Earth
occur along the
shores of the Pacific
Ocean.
• This region is called
the “Ring of Fire.”
What is the Ring of Fire?
20.2 Where you find volcanoes
• The Ring of Fire is found where the oceanic crust
of the Pacific Plate is subducting under nearby
plates.
• Most volcanoes are located along plate
boundaries.
• Volcanoes, like those in Hawaii are also present
along divergent boundaries and within plates.
Today’s Journey
• 0507.7.1 Create a model to illustrate geologic events
responsible for changes in the earth’s crust.
• 0507.7.2 Prepare a chart to compare how volcanoes,
earthquakes, faulting, and plate movements affect the
earth’s surface features.
• State Performance Indicators
• SPI 0507.7.1
Describe internal forces such as
volcanoes, earthquakes, faulting, and plate movements that
are responsible for the earth’s major geological features
such as mountains, valleys, etc.