Volcano – Definition, Types & Distribution of Volcanoes

By Balaji

Updated on: March 9th, 2023

A Volcano is an opening in the earth’s crust, and through this, ash, steam, lava, gases, etc., erupts. Such openings in the earth’s crust occur where the rock strata are relatively weak. There are both explosive and non-explosive Volcanoes. On the basis of the explosive nature of the Volcano, different landforms can be formed, such as mountains (if it is explosive) and plateaus (if it’s not explosive).

Volcano is a part of the geography section of the UPSC Syllabus, and candidates can expect a few questions related to this topic. In this article, we have provided Volcano UPSC Notes that would help the candidate prepare effectively. Here we have mentioned the major types of Volcanoes from which questions can be asked.

Table of content

  • 1. What is Volcano? (more)
  • 2. Types of Volcanoes (more)
  • 3. Volcano: Interesting Facts (more)
  • 4. Distribution of Volcanoes in the World (more)
  • 5. Volcano UPSC (more)

What is Volcano?

Volcanoes are explained as mountains or landforms. Here the molten rocks appear from the planet’s surface, and Volcano mountain opens under the molten rocks pool inside the surface of the earth.

Volcano UPSC Notes

  • In other words, a Volcano can be defined as a fissure or vent in the earth’s crust where ash, gases, lava, etc., come out.
  • Those Volcanoes that have appeared in the recent past are named Active Volcanoes.
  • Magma is the term used to describe the related materials and molten rocks spotted inside the earth. When the magma comes out to the surface of the earth through Volcano’s vent, it is called Lava.

Types of Volcanoes

The Volcanoes have been classified on the basis of their eruption and the form developed on the surface. We have mentioned the Types of Volcanoes below.

Shield Volcanoes

  • These are the largest Volcanoes active currently on the earth’s surface, and they are made up of basalt.
  • These Volcanoes can become explosive if water goes inside the vent. Otherwise, these are less explosive in nature.
  • The shield Volcanoes have low slopes, and they consist of frozen lavas.
  • The upcoming lava comes in fountain form and throws out the cone at the vent’s top, and develops into a cinder cone. One example of shield volcanoes is Hawaiian shield volcanoes.

Composite Volcanoes

  • Composite Volcanoes are characterized by outbreaks of viscous and cooler lavas than basalt.
  • These Volcanoes formed from many explosive eruptions.
  • The materials gathered near the openings of the vent result in the formation of layers.
  • A significant amount of ashes and pyroclastic gets wiped out with lava.

Caldera Volcanoes

  • These are known as the most explosive Volcanoes on the planet.
  • These Volcanoes are mostly explosive in nature, and during eruptions, they collapse on themselves. This collapsed depression is known as calderas.

Mid-Ocean Ridge Volcanoes

  • These Volcanoes are spotted in oceanic areas.
  • The central part of the ridge witnesses frequent eruptions

Flood Basalt Provinces

  • These Volcanoes discharge highly fluid lava that travels for long distances.
  • Many places in the world are covered by thick basalt lava flows.

Volcano: Interesting Facts

The formation of a Volcano is due to the eruptions of ash and lava.

  • The Volcano looks like a cone-shaped hill or mountain.
  • When the magma reaches the surface of the earth, it is referred to as lava. On cooling down on lava, it leads to the formation of rock.
  • There are some Volcanoes that can also occur inside the water.

Distribution of Volcanoes in the World

Most of the Volcanoes are found in the three belts of the world namely- The circum-Pacific Belt (The Pacific Ring of Fire), the Mountain belt in the Middle World, and the Belt of the African Rift Valley.

  • Volcanoes are not spread over the world randomly, and most of them are found in the island chains, beneath the sea.
  • Scientists have developed a hypothesis that Plate Tectonics is responsible for the different locations of Volcanoes.
  • Less intense and more fluid basaltic discharges are produced by volcanoes at divergent borders.
  • Hot spot Volcanoes are the least active due to their location, and there is no sign of Volcanic activity where the continents collide.

Volcano UPSC

Questions related to Volcanoes and Types of Volcanoes can be asked in the UPSC Exam as this topic is a part of the UPSC Syllabus. So, candidates need to be prepared with the Volcano UPSC notes that would help answer all the questions asked on this particular topic. In addition, candidates can also follow standard UPSC Books and other study materials to know about this topic in detail.

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