The 18 types of volcanoes (and their characteristics)

A volcano is a geological structure formed by an opening or crack in the earth's crust that connects, through a conduit or chimney, with a magmatic chamber located inside the Land. Incandescent materials, gases and water vapor from the inner chamber will be expelled through the crater or opening in the form smoke, flames and burning or melted matter, thus forming, by deposition and accumulation, the external structure that we see. In this article we will classify the different types of volcano, describing their most representative characteristics as well as naming a recognized example of each one.

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How are volcanoes classified.

We can classify volcanoes into different types according to: their activity, their eruption and their shape. We will present them below.

1. Types of volcano according to their activity

This distinction between volcanoes will be made taking into account the frequency of eruption of each one.

1.1. Active volcanos

Active volcanoes are those that are in eruption or that they are in a latency period (period between eruption and eruption) and can erupt at any time. It is in this state that most volcanoes are found, since they are not continuously active, but that remain at rest most of the time, with the possibility of producing eruptions in different epochs.

The time that the volcano can be expelling incandescent materials is very variable and extensive, and can last from hours or even years. At present, some of the volcanoes that are still considered active could be: Mount Vesuvius in Italy, the Galeras in Colombia and that of the Cumbre Vieja in La Palma, Canary Islands, a volcano that currently, in 2021, is in eruption.

1.2. Dormant or dormant volcanoes

Dormant or dormant volcanoes are those that they haven't erupted in centuries. They have a long latency period, that is, a long period of inactive time elapses between eruption and eruption. Even so, if there is a low or minimal activity, it can be activated sporadically, showing the presence of hot springs, water with a high amount of minerals that comes out of the interior of the Earth in a natural way and showing a temperature higher by 5ºC than that which occurs in the surface.

Within this type of volcanoes can also be included those that produce fumaroles, which is a mixture of gases and vapors that escape to the outside through the cracks of the volcano at high temperatures. It is important to remember that these are not extinct, they are still active and with the possibility of erupting, a fact that makes it possible to observe movements or slight earthquakes in the areas close to them. To give an example of inactive volcanoes, we can name: the Villarrica volcano in Chile, the Teide in the Canary Islands, Spain or the Etna volcano in Sicily.

1.3. Extinct volcanoes

Extinct volcanoes are those that they last erupted more than 25,000 years ago. Everything and not having presented activity for a long period of time, this does not mean that in the future it cannot erupt again, therefore, it does not appear completely extinct. Also classified as extinct volcanoes are those that the movements of tectonic plates have caused their magma source to shift. As examples of this type of volcano we could mention: Mount Kilimanjaro in Tanzania and Diamond Head in Hawaii.

2. Types of volcano according to its eruption

Volcanoes can also be classified depending on the type of eruption they present, this will depend on how they are the magma, what temperature it has, what viscosity, how is its composition and what elements are dissolved in he.

2.1. Hawaiian volcanoes

Hawaiian volcanoes are what they present eruptions of fluid, not very viscous lava, no gas evolution occurs or explosions are generated, since they do not have many pyroclastic materials, hot mixture of gases, ash and rock fragments. Lava slides easily, releasing gases little by little and without producing explosions, a fact that makes the eruptions silent. As its name indicates, these types of volcanoes are those that are mainly found in Hawaii, as is the case of Kilauea, one of the best known volcanoes in this State.

2.2. Strombolian volcanoes

This type of volcano presents successive explosions, launching pyroclastic material. Lava is viscous and not very fluid, causing that when it descends, it slides down the slopes and ravines without reaching great distances.

The less fluid consistency of the lava causes it to crystallize as it rises through the duct or chimney and Launches of this take place in the form of semi-consolidated lava balls, which are called volcanic projectiles. Strombolian lava produces abundant gases and easily, due to this no sprays or ashes are observed. The name of this type of volcano coincides or is related to the Stromboli volcano, located in Sicily, Italy.

23. Volcanoes volcanoes

Vulcan volcanoes have very violent eruptions that can lead to the destruction of the volcano itself. Lava is very viscous and there are strong explosions that produce sprays and a lot of ash.

Large clouds of pyroclastic material are generated, with a characteristic mushroom or fungus shape. Lava, being not very fluid, consolidates quickly, reaching little reach on the outside and causing the cone, the external part of the volcano, to present a very steep slope. This type of volcano owes its name to the Vulcano volcano located in Italy.

2.4. Fighting volcanoes

The fighting volcanoes produce very viscous lava that causes it to quickly consolidate forming a plug in the crater. The force that continues to generate the internal gases to be able to escape, causes either side cracks to open when the walls give way or the high pressure that is exerted ends up causing the plug to be ejected in a violent The best known example and for which this volcano is named is Mount Pelée on the island of Martinique.

2.5. Hydromagmatic volcanoes

The eruption of hydromagmatic volcanoes occurs when magma comes into contact with groundwater or surface water, thus producing the release of large amounts of steam. These types of volcanoes have characteristics similar to those already named Strombolians, but unlike the latter, the lava of the hydromagmatic ones is more liquid. We find this type of volcano, for example, in the Campo de Calatrava region in Spain.

2.6. Icelandic or fissural volcanoes

In the Icelandic volcanoes the lava produced is fluid and the eruptions are expelled from fissures (cracks) that appear on the ground, not around the crater as most do. This fact, when the lava comes out through lateral cracks, causes large plateaus to form in the area of ​​the volcano, creating a flat relief, instead of very steep slopes. As the name indicates, these types of volcanoes are usually found in Iceland.

2.7. Underwater volcanoes

The eruptions that produce these types of volcanoes tend to be short-lived, as the lava cools when it comes into contact with water and due to the erosion caused by the sea. Therefore, although it is strange that a volcano can erupt in waterThis fact is very common, thus being able to generate volcanic islands when the lava reaches the surface and condenses when it cools. An example of this type of volcanoes close to us are those that gave rise to the Canary Islands here in Spain.

2.8. Plinian or Vesuvian eruption volcanoes

Lava produced in the Plinian eruptions it is very viscous, acidic in character, giving rise to very violent explosions. Gases are continuously expelled at high temperatures and large amounts of ash, these can cover large areas.

The explosions can generate pyroclastic flows also called burning clouds or pyroclastic flow, which are a mixture of gases and solid materials hot and trapped air, which when expelled, precipitated, outside the volcano, can bury large areas of land in a very short period of time, in minutes. The condensed material that is produced in pyroclastic flows is called ignimbrite rock. The well-known case that occurred in Pompeii and Herculaneum, which were buried by the eruption of the Vesuvius volcano, is a typical example of this type of volcano.

2.9. Phreatomagmatic eruption volcano or Surtseyana

This type of eruption occurs when magma interacts with water, either from the subsoil, from the thaw or from the sea. When the two fluids collide at very different temperatures, makes the explosion very violent, since the energy of the volcano is combined with the expansion of the water vapor.

The proportion of water and magma has to be determined, on the contrary if there is a lot of water it will cool the magma and they will not be produced explosions and if, on the contrary, the amount of magma is much higher, it will cause the water to evaporate and be consumed without producing no effect. An example of this type of eruption would be those produced by the Anak Krakatoa volcano in Indonesia.

2.10. Cieno eruptions volcano

When the volcano is at rest, water accumulates in the crater, forming lakes or ice. This will cause that when the volcano is activated again the ashes and material that it expels joins with the water thus generating avalanches of silt, soft mud that is deposited at the bottom of places where there is water accumulated.

3. Types of volcano according to its shape

In this section we will classify the types of volcanoes that exist according to their shape.

3.1. Shield volcanoes

The fluid lava and the successive accumulation of eruptions create large volcanoes characteristic for having a large diameter but low height. The most active shield volcano is the previously named Kilauea volcano in Hawaii.

3.2. Stratovolcanoes

This form of volcano is created by the alternate production of violent eruptions and quiet eruptions, giving it a high-rise conical shape. The material that constitutes the shape of the volcano are layers of lava together with layers of rock. The Colima fire volcano in Mexico would present the shape of this type of volcano.

3.3. Volcanic calderas

This form appears when generating great explosions or subsidence of the magmatic chamber, giving rise to a large crater more than 1 kilometer in diameter. The caldera de las Cañadas on the island of Tenerife would be an example.

3.4. Cinder or slag cones

Formed by the accumulation of ash and small in size, no more than 300 meters high, this volcanic form is the one that occurs mostly on Earth. An example of cinder cones is the Paricutín volcano in Mexico.

3.5. Lava dome

The volcanic domes, bulbous, swollen mass of solidified lava, are created from explosive eruptions, the lava that is expelled is viscous, little fluid, remaining accumulated and covering the crater. One of the most active lava domes in the world is located on Mount Merapi in Indonesia.