What are the three main
volcanoes?
There
are three main types of volcano - composite or strato, shield
and dome.
Composite
Composite
volcanoes, sometimes known as strato volcanoes, are steep sided
cones formed from layers of ash and [lava]
flows. Composite volcanoes can rise over 8000 feet. Examples of
composite volcanoes include Mount Fuji (Japan), Mount
St Helens (USA) and Mount
Pinatubo (Philippines).
![[a cross section of a composite volcano]](../images/composite.gif)
A simple cross section through a composite volcano
When
composite volcanoes erupt they are explosive and pose a threat
to nearby life and property.
Shield
Shield
volcanoes have gently sloping sides and are formed from layers
of lava. Eruptions are typically non-explosive. Shield volcanoes
produce fast flowing fluid [lava]
that can flow for many miles. Examples of shield volcanoes include
the Hawaiian
volcanoes. Although these eruptions destroy property, death
or injury to humans rarely occurs.
Dome
(Acid Lava Cones)
Acid
[lava]
is much thicker than [lava]
which flows from shield volcanoes. Dome volcanoes have much steeper
sides than shield volcanoes. This is because the lava is thick
and sticky. It cannot flow very far before ot cools and hardens.
An example is Puy de Dome in the Auvergne region of France which
last erupted over 1 million years ago.
|