Volcano

What is a Volcano?

The volcano definition can be put as a generally conical landform like a hill or mountain with a vent (or opening) from where materials like lava, volcanic ashes, and other gases erupt. One of the major reasons behind the volcanic eruption is due to the pressure that is created due to the dissolved gases. In other words, a volcano eruption can be seen as similar to that of opening a bottle of soft drink, where the pressurized gases spew outwards.

 

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One of the volcanic mountain examples is Mount Garibaldi. This is a potentially active volcano that is located southwest British Columbia.


Formation of Volcanic Mountains

The formation of volcanic mountains takes place from the surface eruption of magma. This is mainly present in Earth’s upper mantle. Once the magma erupts, it comes out to the surface, forming lava that flows, depositing ashes. The formation of mountains takes place, as continuous eruption takes place, and new layers of lava are added on top of each other.


The Different Stages of Volcanoes

One can extract more information about volcanic mountains after learning the different stages of formation. The shape of the volcanic mountain tends to differ based on the following circumstances:

  • The kind of material erupted from the volcano

  • The exact kind of eruption

  • The overall change after the eruption

 

Categories of Volcanoes

  • Active Volcanoes: The volcanoes that are labeled as active volcanoes have the tendency to erupt at any given point of time. In fact, there are active volcanoes that are erupting already.

  • Dormant Volcanoes: Dormant Volcanoes are the ones that have not erupted for a long time, but they are expected to erupt in the distant future.

  • Extinct Volcanoes: The volcanos which have not erupted for tens of thousands of years and are not likely to erupt in the future are generally termed as extinct volcanoes.

 

How does Volcanic Eruption Occur?

If you are wondering how volcanic mountains are formed, they occur in the following way. At first, during the eruption, the magma or molten rocks rise above the surface. The formation of magma takes place when the Earth’s mantle melts. Such melting occurs due to the high pressure exerted on them. Such pressure is caused by the movement of tectonic plates, either pulling apart or pushing towards one another.


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Magma is generally lighter than rocks. So, as the magma gradually rises to the floor, bubbles start to form within. Runny magma, on the other hand, erupts from the vents that are formed within the Earth’s crust, before even flowing over the surface. When too much pressure is formed during volcano formation, it rises with an explosive eruption. The magma which flows out and comes in contact with air is called lava.


Types of Volcanoes

Generally. one can find four major types:

  • Cinder Cone Volcanoes

  • Composite Volcanoes

  • Shield Volcanoes

  • Lava Domes


Cinder Cone Volcanoes

These are the simplest volcanoes to be formed. The cinder cone volcanoes are formed when small particles and other blobs of lava ejects out of the volcanic vents. The lava spews into the air and small pieces of the same gather around the vent. As time passes by, it gradually forms a bowl-shaped crater. Another important aspect of the volcano is that these mountains hardly grow larger than 1000 feet. Eg. Mauna Loa Volcano, Hawaii.


Composite Volcanoes

Some of the most renowned mountains are actually made out of composite volcanoes. They are often termed as stratovolcanoes. Mount Fujiyama and Mount Cotopaxi are some composite volcanic mountain examples. The conduit systems built within the mountain helps them to actually channel the magma from the Earth’s crust. They are built of many layers of pumice, hardened lava, and ash. 


Shield Volcanoes

These volcanoes have a shield-like shape when observed from above. They are made of fluid lava flows and due to highly fluid lava, which travels far from the site of eruption. Since they stretch over a long distance and eventually solidify, there is a slow accumulation of broad lava sheets giving a distinct form to this volcano. A good example of such a mountain is the Volcán Wolf.


Lava Domes

Finally, there are the lava domes. These are formed from small masses of lava that stay in one place. Due to their more viscous nature, they become too thin to even move from one place to another. The only way these domes can grow is through the accumulation of lava building up inside them. Lava domes tend to explode violently, as a result of which, it creates a large chunk of hot rocks and ashes. Eg. Atwell Peak, British Columbia.

FAQ (Frequently Asked Questions)

1) State the Difference Between Lava and Magma?

Going deep into volcano details, Lava and Magma are two terms that are very loosely used in a similar fashion. Magma can be defined as the liquid rock that builds up inside the volcano. Lava is the liquid rock that actually flows out of the volcano and comes in contact with air. If you look at freshly drawn out lava, they are generally red to white-hot in colour. One of the major reasons why lava takes such a long time to cool is due to poor conductivity. Their vicious nature results in a very slow flow while slowing down the hardening rate at the same time.

2) What are Lahars and Pumices?

Both lahars and pumices are different components of volcanoes. Lahars can be defined as the flow of debris, that mainly comprises pyroclastic materials. While flowing down from the mountain, they take the shape of a river. Lahars are as dangerous as the lava itself. While they are moving, they retain their liquid state, but as they stop, it solidifies. Pumice, on the other hand, is a kind of lightweight, porous volcanic rock. They are mainly formed during volcanic eruptions. Their shape greatly resembles that of a sponge, due to the gas bubbles that get frozen inside them. It can be formed out of any magma.