Directions: Read the information below. Use this information and your book to complete the lab procedure below.
A cinder cone is a steep conical hill formed above a vent. Cinder cones are among the most common volcanic landforms
found in the world. They aren't famous as their eruptions usually don't cause any loss of life. Cinder cones are chiefly
formed by Strombolian eruptions. The cones usually grow up in groups and they often occur on the flanks of strato
volcanoes and shield volcanoes. Cinder cones are built from lava fragments called cinders. The lava fragments are ejected
from a single vent and accumulate around the vent when they fall back to earth. Cinder cones grow rapidly and soon
approach their maximum size. They rarely exceed 250m in height and 500m in diameter.
Shield volcanoes are huge in size. They are built by many layers of runny lava flows. Lava spills out of a central vent or
group of vents. A broad shaped, gently sloping cone is formed. This is caused by the very fluid, basaltic lava which can't
be piled up into steep mounds. Shield volcanoes may be produced by hot spots which lay far away from the edges of
tectonic plates. Shields also occur along the mid-oceanic ridge, where sea-floor spreading is in progress and along
subduction related volcanic arcs. The eruptions of shield volcanoes are characterized by low-explosivity lava-fountaining
that forms cinder cones and spatter cones at the vent. Famous shield volcanoes can be found for example in Hawaii.
Composite volcanoes, also called strato volcanoes, are formed by alternating layers of lava and rock fragments. This is
the reason they are called composite. Composite volcanoes usually erupt in an explosive way. This is usually caused by
viscous magma. When very viscous magma rises to the surface, it usually clogs the craterpipe, and gas in the craterpipe
gets locked up. Therefore, the pressure will increase resulting in an explosive eruption.
Volcano Types Lab
The type of volcano that forms is directly related to the type of eruption and the type of lava a volcano has. In this lab
you will be researching how each volcano forms, making a sketch of each volcano and then making a model of each
volcano.
Procedure:
1. Use your book/computer to describe how each volcano is formed.
2 Identify what type of eruption each volcano has.
3. Identify the type of lava/pyroclastic material each volcano has.
4. Make a sketch of each volcano.
5. Create a detailed model of each volcano using clay. (Your model should be similar to the diagrams on p. 228 in your
book. You should show the inside parts of the volcano by cutting your model in half to create a cross section and then
add the layers, magma chamber, pipe, and vents. See page 224 and the diagrams above)
Volcano
Type
Description of How
Volcano Forms
Built out of layers of
lava from repeated
non-explosive
eruptions. The lava is
very runny, so it
spreads out over a
wide area forming a
gently sloping volcano.
Type of
Eruption and
Type of
Lava/Pyroclastic
Material
Non-explosive
eruption.
Very runny lava.
Lava has a low
viscosity, which
means it flows
easily.
Shield
A small, very steep
volcanic cone made
entirely of pyroclastic
material from
moderately explosive
eruptions.
Moderately
explosive eruption.
Most common type of
volcano. They are
formed from explosive
eruptions of ash and
cinders followed by
less explosive eruptions
of lava. These
alternating eruptions
form distinct layers of
pyroclastic material
and lava.
First, there is an
explosive eruption
of pyroclastic
material, which is
followed by a
second nonexplosive eruption
of lava.
Cinder
Cone
Composite
Very little lava
erupts. Cinder-cone
volcanoes mostly
erupt cinders or ash
which is what builds
the steep side of the
volcano.
Sketch of Volcano