Points to Consider
- What types of evidence do you think would tell scientists whether an ancient volcanic
eruption was explosive or non-explosive? - Are all volcanoes shaped like tall mountains with a crater on the peak?
- What do you think is the origin of the names A’a and Pāhoehoe?
- Earthquakes do not always indicate that a volcano is going to erupt. What factors
about an earthquake might indicate a relationship to a volcanic eruption?
8.3 Types of Volcanoes
Lesson Objectives
- Describe the basic shapes of volcanoes.
- Compare the features of volcanoes.
- Describe the stages in the formation of volcanoes.
Introduction
When most people think of volcanoes, they think of a tall mountain with a crater on the
top, maybe a little snow at the summit and some trees scattered around the base. There
are many volcanoes like this, but volcanoes exist in many other forms as well. Each type
of volcano has characteristic features that distinguish it from other types. Volcanoes differ
in appearance because of the composition of their magma and the processes that originally
created them.
Types of Volcanoes
The tall cone shape you usually think of when you think of a volcano describes a composite
volcano, one common form of volcanoes. Other types of volcanoes include the shield volcano,
the cinder cone, and the supervolcano.
Composite Volcanoes
The picture above shows Mt. Fuji, a classic example of the composite volcano (Figure8.21).
This is the type of volcano many people think of when they imagine volcanoes. Composite
volcanoeshavebroadbasesandsidesthatgetsteeperandsteeperasyougetclosertothetop.
These volcanoes frequently have a large crater at the top created during its last eruption.