Volcanoes are largely responsible for the creation of the lithosphere. Throughout our planet’s geological history volcanoes have moulded the surface of the earth, influenced climate and played an important role in some moments of humanity’s history. But not all volcanoes are equal. Would you like to discover them?
But before we go into how they are classified, do we have a clear idea of what a volcano is? A volcano is a geological structure that consists of a crack in a solid surface through which magma, a mixture of solids, liquids and gases at a very high temperature, from the depths of the earth’s crust emerges to the surface. The magma that is ejected during volcanic eruptions is called lava.
The accumulation of material by the opening of the conduit creates a conical structure that can rise hundreds or thousands of metres high. The depression at the summit of this mound is called a crater.
How do you classify volcanoes?
Active volcanoes are those that began erupting from the last glacial period 10,000 years ago. We have roughly 1,500 potentially active volcanoes currently on Earth.
These are volcanoes that have not begun erupting and are not expected to erupt in the future, for a long period of time.
Classifying volcanoes according to their shape
There are different types depending on their structure and form:
This is the simplest type. It is formed by the accumulation of ash and scoria around a single volcanic conduit forming a conical structure. This type of volcano is found in abundance in the eastern part of North America.
- Composite volcanoes or stratovolcanoes
This type of volcano is the most common and represents around 60% of the total number. Its main characteristic is the existence of a system of conduits through which the magma, stored in a magma chamber in the lowest part of the crust, rises to the surface.
Some of the highest mountains in the world, such as Mount Fuji in Japan, Kilimanjaro in Tanzania or the Teide in Spain, are composite volcanoes or stratovolcanoes.
- Shield volcanoes
These are made up almost exclusively of highly liquid basaltic lava that emerges from the conduit or group of conduits of the volcano and flows out in all directions, covering huge distances. The islands of Hawaii are a chain of volcanoes of this type, including the Kilauea, which is one of the most active in the world.
- Lava domes
These are a type of volcano that is almost circular in shape because the lava flows of the eruptions are so thick that they do not move to cover long distances. We find lava domes in the Hawaiian Islands and in California.