Discover the POWERFUL Secrets of VOLCANOES Today!

We explain what a volcano is, its classification and the types of activities it presents. Also, its general characteristics and more.

What are volcanoes?

The volcanoes They are mountain-shaped openings in the earth's surface, which have an upper crater through which different magmatic materials (in gaseous, liquid and solid states) that come from the interior of the Earth can be expelled.

A volcano is generated when magmatic materials, which reach a high temperature and great pressure, release that pressure after a movement occurs in the plates that make up the Earth's crust. The magma flows through the cracks and has a lower temperature the closer it gets to the surface. This change in temperature generates the explosion of lava.

Volcanoes are not always active. A volcano is considered active when it can expel magmatic materials on a regular basis.. The type of volcanic eruption depends on the temperature, composition, viscosity and elements of the magma.

A volcano is considered inactive or dormant when, deep within the Earth, the magma does not reach sufficient temperature or pressure to generate an explosion towards the surface. The resumption of a volcano's activity can never be ruled out with complete certainty, however, volcanoes that have not recorded eruptions in the last hundred years are considered extinct.

Characteristics of volcanoes

Among the main characteristics of volcanoes, the following stand out:

They are mountains or hills in conical shape They have a crater at the top.
They have the surface covered in lava and ashes coming from previous eruptions that, as they cool, harden and form igneous rocks that accumulate and accentuate the conical shape of the volcano.
They can erupt lavawhich is the magma from inside the Earth that comes to the surface and can reach between 4 and 200 kilometers in height during the explosion.
They have internal cracks through which the magma flows, which, depending on its composition, can reach temperatures between 700 and 1300 ºC.
They are capable of build up great pressure and temperature inside.
They erupt when tectonic plates move and the internal pressure of the volcano is released through the crater, causing the magma to explode.

Structure of volcanoes

The structure of the volcanoes is made up of:

Magmatic chamber. It is the deepest part beneath the Earth's crust in which molten lava accumulates from the mantle, an even deeper Earth layer. The lava buildup mixes with other materials, such as gases and water.
Dome or shelf. It is formed by accumulations of lava that do not reach the earth's surface, but cool between the layers of underground rock.
Chimney or flue. It is the channel that connects the magma chamber with the crater or external opening of the volcano, through which the erupting magma rises.
Volcanic cone. It is formed by the accumulation of solidified lava on the surface of the volcano, from previous eruptions. As time goes by and with each eruption, the cone takes on an increasingly pronounced shape.
Fissures. They are small cracks through which magma or gases are expelled to the surface, with less intensity than the materials that erupt from the volcanic cone.
Crater. It is the exterior opening of the volcano located at the top, through which it expels lava. The size of the crater can vary with each eruption, depending on the intensity and level of destruction of the explosion.

Types of rashes

The types of volcanic eruptions depend on the temperature, composition and viscosity of the magmatic elements. There are three general types of eruptions: magmatic, phreatic and phreatomagmatic eruptions.

Magmatic eruptions are those that occur when magma emerges to the surface. They are classified into six types:

Hawaiian eruptions. They are eruptions that occur in the volcanoes of the Hawaii region, which is a volcanic archipelago that constitutes one of the states of the United States. They are characterized by being the calmest eruptions with intense explosions of lava and low levels of gaseous and ash components.
Strombolian eruptions. They are eruptions in which the lava is very fluid and releases abundant and violent gases that can reach hundreds of meters away during the explosion. No ash is produced and the lava that runs across the surface of the volcano does not reach as long an extension as the Hawaiian eruptions.
Vulcanian eruptions. They are eruptions made up of a large amount of gases and, due to the fluid lava that is pulverized by the gases, an intense presence of ash is generated. The conical shape of these volcanoes is very pronounced due to the accumulation of solidified ash.
Plinian eruptions. They are eruptions caused by gases and are more violent than Vulcanian eruptions. They form fiery clouds that, when cooled, precipitate in the form of ash and can reach a large size.
Fighting eruptions. They are very explosive eruptions that emanate consistent lava accompanied by clouds made up of gases, water vapor and ash, and that are capable of destroying everything they can cover.
Fissure eruptions. They are eruptions that originate due to an extensive dislocation of the Earth's crust, in which lava flows along the crack. The lava from these eruptions, when it cools, can rise to the surface and form islands such as the Canary Islands (Spain) or the Cyclades Islands (Greece).