When the earth burps
Volcano parts
Volcanism

Any movement of magma inside Earth
is called volcanism.
How Volcanoes Form
Volcanoes form over subduction zones. As
one plate moves under another, it breaks
up and becomes part of the mantle. A
magma chamber is formed and the hot
magma rises to the surface – breaking
through the crust where it deposits lava –
forming a cone and becoming a
VOLCANO.
How subduction works

http://www.classzone.com/books/earth_sc
ience/terc/content/visualizations/es0902/e
s0902page01.cfm
Crater

At the top of a volcanic cone there may be
a deep pit. This pit is called a crater. It
forms as material is blown out of the
volcano’s vent.
Calderas
When a volcano
explodes, it leaves a
huge, hollow shell. The
walls of the crater may
fall back into the vent,
leaving a gaping hole
called a caldera.
The Story of Paricutin

In 1943, a farmer in Mexico saw a
mountain form.
The Story of Paricutin
A few weeks later, cracks, called fissures,
appeared and widened. Hot gases began
spewing out of the fissures.
The Story of Paricutin

After several months, a volcanic cone
about 400 m high had formed.
Now Showing
Paricutin: Mountain of Doom
Volcanoes

Classifying by Eruption: Volcanoes may
be classified as quiet or explosive.
 Different
kinds of volcanic eruptions
form different types of volcanic
cones.
Volcanoes
 There
are three types of volcanic
cones:
Shield
Cones
Cinder Cones
Composite Cones
Volcanoes

Shield Cones

This type of volcano is made up of layers
of hardened lava. It’s name is derived
from its shape, it looks like a shield lying
flat on the ground.
Volcanoes

Cinder Cone

Cinder cone volcanoes have steep sides
and narrow bases.
Volcanoes

Composite

This type of cone is made up of layers of
lava and rock particles. A very high, wide
volcanic cone with steep sides.
2 Types of Lava
There are two types of lava that
come from volcanic eruptions.
Hawaiian’s have named them,
Pahoehoe and Aa Aa.
Pahoehoe

is basaltic lava that has a smooth, billowy,
undulating, or ropy surface. These surface
features are due to the movement of very
fluid lava.
Aa Aa

basaltic lava characterized by a rough or
chunky surface composed of broken lava
blocks. It probably got it’s name from
Hawaiian’s walking on it and cutting their
feet.
Can you identify the two types
of lava?
Volcanoes