Several mountains are formed by faulting, folding, uplift and erosion of the crust of the Earth. The vent through which volcanoes occur is visible as a small bowl-shaped depression at a cone or shield-shaped mountain peak. Beneath and within the volcano, there are a series of cracks. The vent connects to one or more linked areas of stored molten or partially molten rock (magma) through this series of cracks. This connection to fresh magma allows the volcano to erupt repeatedly. This happens in the same location. Pieces of volcano collapse as rock falls or landslides. 

What is a volcano?

The volcano is the term that refers to a vent or crack in the Earth, from where there is an eruption of molten rock, hot rock fragments, hot gases and lava. Before eruptions, the material which gets erupted is called magma, but once it is erupted onto the Earth’s surface it is known as lava. 

When do volcanoes occur?

A volcano occurs when significantly warmer material than its surroundings erupts onto its surface. three factors can contribute to the magma rise and volcano eruptions.

1. Sometimes tectonic plates move gradually away from each other. This creates gaps in between which then gets filled by magma subsequently. This gives rise to underwater volcanoes.
2. Conversely, sometimes tectonic plates move towards each other. This causes the earth’s crust to go down into the inner side. This results in an increase in temperature and heat. This all causes Earth’s crust to melt into a magma.
3. The third reason for magma rise is solely the high temperature of the interior of the earth at some specific places. These certain locations are nothing but the hot spots of volcanic eruptions. magma at these locations ,melts repeatedly and rises up to the Earth surface. This causes periodic frequent volcanic eruptions in these areas.

Types of Volcanoes

There are various types of Volcanoes, among which the main three types of volcanoes are mentioned below with details:

1. Strato volcano(or composite volcano) – Strato volcano is a conical volcano. It consists of layers of solid lava flows mixed with other rock layers. Strato volcanoes consist of various layers (or strata) of hardened lava, pumice, tephra and volcanic ash. These volcanoes generally have steep slopes and are known to be the most common type of volcano on Earth. Strato volcanoes’ eruptions are typically explosive and effusive. The most well-known volcanoes of this type include Krakatoa, Mount Helen, Vesuvius, and Mount Tambora. Mount Tambora is the site of the most powerful eruption recorded in history. 

1. Cinder Cone Volcano – Cinder Cone Volcano does not have any horizontal layers. Instead, it is a steep conical hill of volcanic debris (tephra) that accumulates around and downwind from the vent. Cinder cones are made from pyroclastic material and are commonly found on the flanks of shield volcanoes and Strato volcanoes.  Some Cinder Cone Volcanoes are different from others as they erupt only once. However, these volcanoes have a much less impact than Strato volcanoes. 

1. Shield Volcano – Shield Volcano is a volcano built mostly or entirely from fluid lava vents. These volcanoes have very gentle slopes built by effusive eruptions, which flow out in all directions. These volcanoes rarely have violent eruptions and are accompanied by lava simply flowing out. 

Layers of Volcano

The different layers of a volcano include:

1. Magma Chamber 
2. Bedrock
3. Pipe
4. Ash Layers
5. Lava Layers
6. Lava Flow
7. Vent
8. Ash cloud
9. Ash Layer

There are a total six active volcanoes and one extinct volcano situated in India. the list is given below-

1. Barren Island- location Andaman Sea
2. Narcondam Island- location Andaman Sea
3. Deccan Traps-location Deccan plateau, Maharashtra
4. Baratang Island-location Andaman Island
5. Dhinodhar Island-location Gujarat
6. Dhosi Hills- location Aravali mountain range, Haryana
7. Tosham hill- its an extinct volcano located in Haryana.

   Conclusion:

   There are various types of Volcanoes on Earth, some are extremely eruptive, and some erupt only once. This article will help me learn the basic details about the types and features.