Volcanoes are classified by the eruption type and by the volcanic cone shape.
There are three basic cone shapes and six eruption types. The three cone shapes are cinder cones, shield cones, and composite cones or stratovolcanoes.

 

The six eruption types are in order from least explosive to the most explosive; Icelandic, Hawaiian, Strombolian, Vulcanian, Pelean, and Plinian.
Notice how, as the eruptions become more violent, the cone shapes become more steeply constructed.

Icelandic, flood, or fissure eruptions are all terms for volcanic eruptions that flood the surface of the Earth with massive amounts of very hot, very thin, runny lava. The lava comes out of the ground through long cracks in the surface called fissures. Some of these fissures can be up to 15 miles long.  The type of cone produced from Icelandic eruptions is a shield cone. Shield cones are very low and very broad shaped volcanoes. These volcanoes erupt many times over the same area forming huge, and thick lava plateaus.

The Deccan Plateau of India was formed this way and covers 100,000 square miles. The Columbia Plateau of the western United States is the largest lava plateau in the world. It covers almost 100,000 square miles and is almost a mile thick in places.

Hawaiian eruptions are similar to Icelandic eruptions because both eruption types have many fissures bringing the lava to the surface. Both types of eruptions are known for their beautiful fire fountains like the one shown above. The lava that flows from both types of eruptions is very hot, thin, and runny which allows for fast flowing lava flows.
The main difference lies in the fact that most Hawaiian eruptions have the greatest quantity of lava pouring out of the main vent at the volcano's summit, not along side fissures. These summit eruptions build the cone steeper and higher. The volcano on the next card was formed from Hawaiian eruptions.

Strombolian and Vulcanian eruptions are more explosive than Icelandic and Hawaiian eruptions.
Strombolian eruptions are named for the volcanic island off of the coast of Italy. Stromboli has erupted over many centuries almost constantly. Stromboli has been named the "Lighthouse of the Mediterranean" because it erupts every 20 minutes or so. Strombolian eruptions are short lived explosive eruptions that shoot very thick and pasty lava into the air along with bursts of steam and gas. Strombolian eruptions usually produce little or no lava. Because of this the cones that are produced by this type of eruption is a very steep sided cone called a cinder cone.

Cinder cones get their name from the material that forms them, cinders. Cinder cones are the simplest volcanic formation. They form from explosions of red, hot magma cinders and ash. These cinders and ash settle around the main vent and build a steep sided cone. Very little lava is erupted from a cinder cone. Cinder cones very rarely rise to more than 1,000 feet above the surrounding landscape. Cinder cones are known for their very violent, explosive, exciting eruptions. Paricutin in Mexico and Mt. Vesuvius in Italy are famous cinder cones.

Vulcanian eruptions are more violent and explosive than strombolian eruptions. Vulcanian eruptions are named after the island of Vulcano off the coast of Italy. This is the same island that gave us the name "Volcano". Vulcanian eruptions contain high dark clouds of steam, ash, and gas. The ash plume builds a cauliflower shaped head and a thinner more treetrunk-like base. When the volcano quits erupting ash and gases it then ejects thick pasty lava. Vulcanian eruptions usually build a steep sided cone that is more symetrical than a cinder cone. This more symetrical cone is called a strovolcano.
 Vulcanian eruptions will send an ash plume to a height of 2 -9 miles.

Stratovolcanoes or composite cones are formed from a combination of eruptions. First the volcano will have an explosive eruption that ejects huge amounts of steam, gas and ash. This will be followed by the ejection of lava. A large stratovolcano will be built with many layers of ash and lava.
  Stratovolcanoes are the most common type of volcanic cone. There are many famous stratovolcanoes in the world. Mt. St. Helens and Rainier in Washington, Mt. Fuji in Japan, Mt. Pinatubo in the Philippines, and Mt. Etna in Sicily are all examples of stratovolcanoes.

Pelean and Plinian eruptions are the most dangerous and explosive of the eruption types. Pelean eruptions are named for the catastophic eruption on the island of Martinique in the Carribean Sea in 1902. The eruption and the pyroclastic flow that followed killed 29,000 people almost instantly. "Glowing clouds" of gas and ash flew down the mountain at over 70 miles per hour. The cloud was so full of ash that it was heavier than air and hugged the ground as it approached the coast. The temperatures were probably around 700 degress F. which would annihalate everything in its path.

The only person to survive was a prisoner that was sentenced to death. The only reason he survived was that he was imprisoned in a very thick walled cell and the only door faced away from the explosion.
A Plinian eruption is the most explosive of the eruption types. Mt. St. Helens eruption was a plinian eruption. Plinian eruptions are characterised by a very high ash cloud that rise upwards to 50,000 feet (almost 10 miles) high. Very deadly pyroclastic flows are also part of plinian eruptions.
Mt. Vesuvius, which erupted in 79 A.D. in Italy, was a classic Plinian eruption. Very hot ash falls killed thousands of people in the city of Pompei. Ash falls as high as 17 feet buried the city. Plinian eruptions were named for Pliny the Elder of Rome who died in one of the many eruptions of Vesuvius.
 

Answer the following:

  1. Name the six eruption types and the three cone shapes.
     
  2. Describe how a: Shield cone form Cinder cone forms Stratovolcano forms
     
  3. Draw diagrams to represent the six eruption types.