Classification of Volcanoes

Types Of Volcanoes According To Shape

One of the marvels on this planet earth is a volcano, which ruptures the crust of the earth and erupts hot magma or volcanic ash. There are different kinds of volcanoes according to shape that are classified as composite volcanoes, cinder cones, lava domes and shield volcanoes. These volcanoes may be active, dormant or extinct in nature. Active volcanoes can erupt anytime and usually the eruption happens often. Dormant volcanoes haven’t erupted for a long while, however you can’t rule out that it won’t happen anytime and extinct volcanoes have not erupted for a long time and hence there are no chances of it erupting again (there have been exceptions to this rule).

Apart from the status of these volcanoes, let us learn about the different kinds of volcanoes according to shape and understand how they explode.

Shield Volcanoes

These kinds of volcanoes according to shape do not explode as the magma inside it is runny, which descends downward hence letting the gas inside the volcano to pass easily. These volcanoes are shaped like a shield or a bowl that has two gentle slopes on the sides that lets the lava flow. The most famous example of shield volcanoes is the running lava in Hawaii.

Composite Volcanoes

In these types of volcanoes the magma is sticky and dense – the texture of maple syrup. Due to the dense magma, the gas has no path for escaping, ultimately leading to the gas getting built up and exploding due to too much pressure. The explosion erupts huge dark cloud of gas and burning rocks. These kinds of volcanoes according to shape are steep and consist of many layers of volcanic rock. The most famous examples of Composite volcanoes are Mt. Fuji in Japan and Mt. Etna in Italy.

Cinder Cones

As the name suggests these kinds of volcanoes according to r are circular or in an oval shape that is built from lava that erupts and gets broken in to small particles in the air. When these small particles land on the ground cool they form cinder blocks or cinder cones around the opening. Some of the most famous examples of cinder cones are Capulin Volcano in New Mexico.

Lava Domes

These are the most commonly seen volcanoes as depicted in movies and animation. The shape of these domes is formed when the lava that erupts is very thick to flow down and hence makes a steep mound towards the sides as the lava loads up near the mouth of the volcano. Some of the most famous examples of Lava domes are Black Butte in California, Mount Tarumae and Mount Kuro in Japan, Pharaoh Dome in Canada and Mont Gerbier de Jonc, in France

Volcano eruptions can cause a lot of heat in the surrounding areas due to the boiling magma. Ash cloud is a common side effect of most erupted volcanoes and can disrupt air travel that passes through the area of the ash cover completely for a long time. In this way volcanoes can be categorized in accordance with the shape.

Kinds Of Volcanoes According To Activity

Active Volcanoes

As the name suggest, active volcanoes are the type of volcanoes that in general have been active for a certain period of time. However there is no consensus among most scientist on the matter of how long ago should the volcano have erupted to consider it an active volcano. Considering the facts that most active volcanoes have erupted around a dozen times in the past 10,000 years, this period of time is safely assumed for a volcano eruption to be considered active. As off today there are about 1500 active volcanoes in the world and about 50 of them erupt every year. Some common examples of active volcanoes in the world are Mount Fuji I Japan, Kilauea in Hawaii, Santa Maria in Guatemala and Mount Etna in Italy.

Dormant Volcanoes

There is a general confusion in understanding the difference between an active and a dormant volcano. Most of the time these dormant volcanoes are assumed to be inactive for more than thousands of years however there have been several exceptions to this rule. There are many volcanoes that have erupted when the chances of them ever erupting were next to nil but they surprised everyone by erupting after thousands of years. These kinds of volcanoes according to activity can cause the most damage as the eruptions are not expected and people are not generally prepared. There could be settlements living around these dormant volcanoes that can face the most damage. They are now commonly known as inactive volcanoes as the volcanic activity cannot be predicted. Some of the common examples of dormant volcanoes in the world are Mauna Kea in Hawaii, Sete Cidades in Portugal, Mount Hood in USA and Mount Teide in Spain.

Extinct Volcanoes

These kinds of volcanoes according to activity as assumed unlikely to erupt as the supply of magma from the volcano is depleted. These volcanoes have not erupted in millions of years and there no chance of any lava or ash eruption as the magma source is completely absent in these volcanoes. Some of the common extinct volcanoes in the world are Mount Ashitaka in Japan, Mount Buninyong in Australia and Kyushu Palau ridge in the Philippines Sea.