Types of Volcano and their characteristics Upsc

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Types of Volcano and its characteristics

The volcanoes are classified based on the nature of the eruption and the form is developed at the surface. The major types of volcanoes are:

  • Shield Volcanoes
  • Composite Volcanoes
  • Caldera
  • Flood Basalt Provinces
  • Mid Ocean Ridge Volcanoes

Shield Volcanoes

Shield Volcanoes
Shield Volcanoes By J.D. Griggs – U.S. Geological Survey, Public Domain, https://commons.wikimedia.org/w/index.php?curid=835932

These volcanoes are the largest of all the volcanoes on the earth and the most famous examples are Hawaiian Volcanoes.

Shield Volcanoes are made of Basalt, which is a type of lava and it is very fluid when erupted.

Due to such a type of lava, these volcanoes are not steep and they become explosive in case water gets into its vent.

Otherwise, the Shield volcanoes are characterized by low explosivity.

The upcoming lava throws out in form of a fountain out the cone at the top of the vent and forms into Cinder Cone.

Composite Volcanoes

Composite Volcanoes By hogeasdf - https://www.flickr.com/photos/9177053@N05/4071658790/, CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=9100465
Composite Volcanoes By hogeasdf – https://www.flickr.com/photos/9177053@N05/4071658790/, CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=9100465

These Volcanoes are featured by eruptions that are cooler and more viscous lava than the basalts.

The composite volcanoes result in explosive eruption and also along with the lava, large quantities of pyroclastic material and ashes were thrown out of the vents.

These materials accumulate in the vicinity of the vent openings leading to the formation of layers which makes these mounts look like composite volcanoes.

Caldera

Caldera
Caldera By unnamed NASA astronaut – This file is in the public domain in the United States because it was created by the Image Science & Analysis Laboratory, of the NASA Johnson Space Center. NASA copyright policy states that “NASA material is not protected by copyright unless noted”. (NASA media use guidelines or Conditions of Use of Astronaut Photographs).Photo source: ISS005-E-6997., Public Domain, https://commons.wikimedia.org/w/index.php?curid=1162697

Calderas is the most explosive of all the volcanoes and they are generally so explosive that they collapse themselves and do not build any structures.

These collapsed depressions are called Calderas.

As the explosiveness of Caldera volcanoes shows that the magma chamber that supplies the Lava is not only big but it is also in close vicinity.

Flood Basalt Provinces

Flood Basalt Provinces
Flood Basalt Provinces By peterhartree – https://www.flickr.com/photos/41812768@N07/15145875322/, CC BY-SA 2.0, https://commons.wikimedia.org/w/index.php?curid=35165591

Flood Basalt Province volcanoes outpour highly fluid lava, which flows for long distances. Some area is covered by thousands of square kilometers of thick basalt lava flows.

Due to a series of flows with some flows attaining a thickness of more than 50m. Also, some flows may extend a few hundred kilometers.

The Deccan Traps from India, presently covering most of the Maharashtra plateau, are a much larger flood basalt province.

Mid-Ocean Ridge Volcanoes

Mid-Ocean Ridge Volcanoes
Mid-Ocean Ridge Volcanoes By 37ophiuchi BrucePL – Based on diagram File:Mittelozeanischer Ruecken – Schema.png. I translated it from German to English and revised outlines of rock units., CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=79658206

It occurs in the oceanic regions and there is such a system of Mid-Ocean Ridges more than 70,000 km long that extends through all the ocean basins. In these ridges, the central portion experiences frequent eruptions.

* * All the Notes in this blog, are referred from Tamil Nadu State Board Books and Samacheer Kalvi Books. Kindly check with the original Tamil Nadu state board books and Ncert Books.