Ever since we were small kids, we always were fascinated about what was in the sky. Ever thought about what is going on beneath the land on which we stand? Let us dive down inside the Earth’s surface and familiarize ourselves with a phenomenon known as the Volcano. You may have seen Volcanic eruptions in movies. Let us learn volcanoes in detail.


Introduction to Volcanoes

Volcanoes are openings on the Earth’s crust through which molten metal comes out. Volcanoes form on the boundaries of the tectonic plates that continuously move inside the Earth. There are 17 such tectonic plates inside the Earth’s Crust. The Earth is divided into several parts such as the Crust, Upper Mantle, Mantle, Outer Core, Inner Core. These tectonic plates exist in the Mantle region inside the Earth. Earthquakes also occur because of the movement of such tectonic plates. Places on the Earth that are on the edges of these tectonic plates are affected the most as these regions are subjected to more amount of underground activity. According to geographical studies, volcanoes generally exist in places where the tectonic plates are either converging or diverging. Volcanic eruption results in polluting the environment as it includes harmful gases and other hot toxic elements including ash.

Formation of Volcanoes and Volcanic Eruptions

Volcanoes are scattered across the planet. Almost about 1500 volcanoes are there on the Earth’s crust and several others are there on the ocean bed. All volcanoes emit gases no matter where they are present. The journey of these emissions begins deep down near the core of the Earth. The core is as hot as the surface of the Sun. Above the core is the mantle layer which is fully present of rocks. The Earth’s core is of very high temperature, because of which the heat converts some portion of the rocky mantle into Magma which has a lower density than the surrounding rocky environment and as a result, it travels upwards and burst out through the openings on the earth’s crust which we know as a volcanic eruption. Once this magma reaches Earth’s surface it is known as lava and has a temperature of near about.

Classification of Volcanoes

There are various kinds of volcanoes primarily classified on the shape and size basis. They are-

  • Strato Volcanoes: These appear as tall steep mountains over the earth’s crust.
  • Shielded Volcanoes: These appear as dome-shaped over the ground.
  • Calderas: These types of volcanoes have large depressions and look like plateaus. A continuous amount of smoke keeps coming out from these types of volcanoes.
  • Ocean- ridges: These are underwater chains of volcanic mountains that exist deep inside the ocean bodies.

Again based on eruptions volcanoes are classified as active or inactive type volcanoes. The volcanoes which erupt on regular basis are termed as active volcanoes and the ones which erupted after a long time (maybe during historical times) are referred to as inactive or dormant type volcanoes.

Ring of Fire

The Ring of Fire is nothing but the path that traces the boundaries of several tectonic plates around the Pacific Ocean which consist of about the world’s 75% of the volcanoes. The Ring of fire covers up regions from Eastern Asia to both North and South America. It is a long chain of about 25000 miles and touches some parts of New Zealand as well.

Famous Volcanic Eruptions

Since the inception of Earth, there has been a lot of volcanic eruptions which were also catastrophic for mankind. Some of them are:

  • Mount Vesuvius in 79 A.D in Italy.
  • Mount Ruiz in 1985 in Columbia.
  • The Mount Tambora in 1815 in Indonesia.
  • Mount Pelee in 1902 in the Caribbean Islands.
  • Mount Krakatoa in 1883 in Indonesia.

In America, there is the famous Yellowstone National Park which consists of the supervolcano. Scientists think that if this supervolcano erupts then it will destroy almost half of the planet. Also, this supervolcano is said to have erupted about 7 lakh years ago.

Effects of Volcanic Eruption on the Environment

Volcanic eruptions releases tons of harmful and toxic elements into the atmosphere. These harmful gases include oxides of carbon and sulfur which have a deadly impact on the ozone layer. Nitrogen dioxide formed also affects the environment. Again, gas emissions as a result of the volcanic eruptions lead to the creation of acid rain as well. Also, aerosols are injected into the Earth’s Atmosphere. When high-temperature ash is thrown out into the environment then sometimes it happens that those particles hit the aeroplanes flying in the sky.

Again when pyroclastic materials mix up with the water in the nearby lakes and rivers, it affects the marine life as well as pollutes the water bodies. Earthquakes are also a result of a high VEI type volcanic eruption. These types of earthquakes are volcano-tectonic earthquakes. These types of earthquakes can have a reading of as high as 7 on the Richter scale. Tsunamis are also a consequence of a devastating volcanic eruption.

Volcanic Eruptions In Solar System

As Earth is a planet and volcanic eruptions have been taking place since its inception, so it is quite obvious that the other planets also experience such a phenomenon. Mars is said to have several dormant type volcanoes. Some moons of Jupiter are said to have an active volcanic system. The planet Venus has a Basalt surface which has been generated because of several volcanoes erupting together. In a nutshell, we can say that a celestial body whose core is hot enough to generate molten metal will experience volcanic eruptions.

FAQs about Volcanoes

Q.1. What is VEI?

Answer: VEI is the volcanic explosivity index. This property depicts various factors of a volcanic eruption such as the volume of lava, gas, and other emissions from the volcano. The VEI scale begins from 0. The most destructive volcanic eruption has a rating of 8 on the VEI scale. Mount Tambora in Indonesia erupted in 1815 with a VEI scale of 7. Also, this was the most destructive Strato volcanic eruption ever witnessed by mankind. This leads to earthquakes and tsunamis as well. This volcanic eruption immediately killed around 10,000 people and later around with various diseases coming into the picture took away more than 1,00,000 lives.

Q.2. What are tectonic plates?

Answer: The tectonic plates are large pieces on the Earth’s crust and upper mantle region which move and collide continuously with each other. The formation of tectonic plates is considered to begin about 3.2 billion years ago. Because of the movement of these tectonic plates, mountains and plateaus, volcanoes form.

Q.3.  What is a pyroclastic flow?

Answer: When a volcano erupts, lots of toxic elements(gases) and molten metal having very high temperature coming out of the volcano opening and flows down through the outer volcanic surface. This can burn down anything in its path. This phenomenon is the pyroclastic flow. The speed of such flow is as high as 725 kilometres per hour.

Q.4. What are aerosols?

Answer: Aerosols are the suspension of solid particles or liquid droplets in another gaseous medium. The volcanic eruptions include aerosols, i.e. solid particles mix with harmful gases and eject out.

Q.5. What is Basalt?

Answer: Basalt is an igneous rock that forms by the cooling of the lava rich in elements such as iron and magnesium.

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