Types of Volcanoes

There are 3 different types of volcanoes:

1. Active - eruptions can be anytime and often.
2. Dormant - has been a while since it has erupted, but could at anytime.
3. Extinct, meaning it hasn't erupted in a very long, long time so it probably won't ever again.
   

Shapes of Volcanoes

How many different shapes of volcano are there?

The type of magma in the earth creates four different types volcanoes:

• shield volcanoes
• composite volcanoes
• cinder cones
• lava domes

Shield Volcano - flat

If the magma is runny, the gas can escape easily and there will not be an explosion. The magma just comes out of the mountain and flows down the sides.

Shield volcanoes are shaped like a bowl or shield in the middle with long gentle slopes made by the lava flows.

Examples include the volcanoes in Hawaii and Mount Etna.

Composite Volcano - tall and thin

If the magma is thick and sticky (like honey), the gas cannot escape, so it builds up and up until it explodes sending out huge clouds of burning rock and gas.

Composite volcanoes are steep-sided volcanoes composed of many layers of volcanic rocks, usually made from thick sticky lava, ash and rock debris (broken pieces).

Composite volcanoes are also known as strato-volcanoes.

Examples include Mount Fuji in Japan, Mount Cotopaxi in Ecuador, Mount Shasta and Lassen in California, Mount Hood in Oregon, Mount St. Helens and Mount Rainier in Washington and Mt. Etna in Italy

Cinder cones

Cinder cones are circular or oval cones built from erupting lava that breaks into small pieces as it shoots into the air. As small pieces fall back to the ground, they cool and form cinders around the vent.

Lava domes

Lava domes are formed when erupting lava is too thick to flow and makes a steep-sided mound as the lava piles up near the volcanic vent.

Glossary