What is a volcano

A volcano is a conical hill or mountain formed by material from the mantle being forced through an opening or vent in the Earth's crust.

What are the main features of a volcano?

What are active, dormant and extinct volcanoes?

Volcanoes are found in three states - extinct, dormant and active. An extinct volcano will never erupt again. A dormant volcano has not erupted in 2000 years. An active volcano has erupted recently and is likely to erupt again. 

 

What are the different types of volcano?

There are a number of different types of volcanoes. The way they are formed depends on a number of factors e.g. the fluidity of the lava (how runny it is) and the temperature of the lava.
Shield volcanoes are common in Hawaii and Iceland. They have gentle slopes and are very wide. Shield volcanoes are formed when lava is very hot and very runny. They consist of many thin layers of rock. Composite volcanoes are steep sided volcanoes. They consist of layers of ash and lava. Composite volcanoes are very explosive because the lava is very viscous (thick). Significant pressure builds within these volcanoes and often results in spectacular eruptions. Examples of composite volcanoes include Mount Pinatubo in the Philippines and Mount Vesuvius in Italy. You can find out more about these types of volcanoes

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).

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.