Volcanoes and volcanic eruptions

In this article, we are going to learn about volcanoes, their formation and their different types and classifications. Complete description of volcanoes is given; comment if you like. You can also follow me for more quality and interesting study material.

Volcano:
A volcano is a process or phenomenon in which a rock after melting forces itself outside the earth. The melted rocks is known as lava. Inside the earth this melted rock is known as magma and when it comes out of the earth it is known as lava. volcanoes are a powerful phenomena.

Types of volcanoes:

 To your surprise, volcanoes are not only red mass flowing outside the earth but it has different types. There are three different types of volcanoes.

• Active volcano
• Dormant volcano
• Extinct volcano

The names of the volcanoes suggest them completely.

Active volcanoes are those kind of volcanoes that have erupted once in their history and there is a chance that they can erupt again ever.

Dormant volcanoes represents those volcanoes that have not erupted even once but there is a predictability that they will erupt in future or near future or any time.

Extinct volcanoes gives us insights about those volcanoes that have erupted in the past but now the possibility of them erupting has completely vanished.

Where do volcanoes occur/erupt?

This is the most unasked question about volcanoes.they just don't erupt from any piece of the land on earth. the volcanoes erupt 90% of the times at tectonic plates. 

 

Fast review: Our earth is not a single piece of crust (upper layer of earth) but it is divided into 16 pieces that are known as tectonic plates.

The different types of movements of tectonic plates cause heat and energy that cause the melting of rocks. These melted rocks make their way out and are called volcanoes.

Classification of volcanoes on different types:

• Shield volcano: 
• Stratovolcano
• Caldera
• Cinder cone

Here's a detailed table about the classified types of volcanoes on the basis of their different shapes, sizes, and lava.

Characteristic	Shield volcano	Stratovolcano	Caldera	Cinder cone
Size	Largest type of volcano	Also large volcano	Large and round	Simplest volcano
Formation	Formed from eruption of highly fluid lava	Formed from eruption and solidification of most explosive lava	Large amount of magma erupts in short time period and results in collapse of rock	Formed as result of eruption of cold lava from a single vent, lava launched violently
Slope	Broad gentle Slope	Steeper slope	Structural support of rock is collapsed	Ash fall as cinders around the vent
Shape	Like a shield	Composite volcano	Looks like cauldron because of collapsed  magma chamber on the top	Circular or oval cone
Example	Mauna Loa	Krakatoa	Santa Ana	Paricutin

What happens with the material or lava that erupts in a volcano?

This erupted lava forms igneous rocks that are extrusive in nature.

 Extrusive rocks are:

• formed of lava
• form outside the earth
• cool down instantly
• have very small or no crystals 
• shiny surface, air bubble spaces due to instant cooling process

If you want to know more about rocks, click here

How do scientists know a volcano is near eruption?

Scientists measure different activities of a volcanic site and then take precautionary measures to prevent life loss and other harms.

For example, scientists measure 

• The widening of cracks 
• The change the gases that erupt
• Increase in seismic activity
• And, swelling of the volcano surface

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