One of the most amazing and mysterious geological formations on Earth are volcanoes. However, many of us have only a superficial understanding of them. What is the nature of volcanism? Where and how is the volcano formed?
What is a volcano?
Before considering the question of how a volcano is formed, one should delve into the etymology and meaning of this term. Ancient Roman myths mention a blacksmith god named Vulcan, whose house was underground. If he was angry, the earth began to shudder, and smoke and tongues of flame erupted from the bowels. It is from here that the name of such mountains came from.
The word "volcano" comes from the Latin "vulcanus", which literally means fire. Volcanoes are geological formations that occur directly above the cracks of the earth's crust. It is through these cracks that lava, ash, a mixture of gases with water vapor and rocks erupt on the surface of the earth. The study of this mysterious phenomenon is carried out by the sciences of geomorphology and volcanology.
Classification and structure
All volcanoes, by the nature of their activity, are active, sleeping, and extinct. And by location - land, underwater and subglacial.
To understand how a volcano is formed, you must first consider in detail its structure. Each volcano consists of the following elements:
- Gerlo (main channel at the center of geological formation).
- Dyke (channel with erupted lava).
- Crater (large hole in the top in the form of a bowl).
- Volcanic bomb (hardened pieces of erupted magma).
- Volcanic chamber (the area under the surface of the earth where magma is concentrated).
- Cone (the so-called "mountain" formed by erupted lava, ash).
Despite the fact that the volcano looks like a huge mountain, its underground part is much larger than the one on the surface. Craters are often filled with water.
Why are volcanoes formed?
The process of formation of a volcano begins with the formation of a magma chamber under the ground. Gradually, glowing liquid magma glows in it, which exerts pressure on the earth's crust from below. It is for this reason that the earth begins to crack. Through cracks and faults, magma erupts upward, and in the process of its movement it melts rocks and significantly widens the cracks. This forms a volcanic vent. How is a volcano formed? During the eruption, various rocks come to the surface, which subsequently settle on the slope, as a result of which a cone is formed.
Where are the volcanoes?
Where do volcanoes form? These geological formations are distributed extremely unevenly on the Earth. If we talk about the laws of their distribution, then a large number of them are located near the equator. In the southern hemisphere, they are much smaller than in the northern. In the European part of Russia, Scandinavia, Australia and Brazil, they are completely absent.
But if we talk about Kamchatka, Iceland, the Mediterranean, the western coast of the Americas, the Indian and Pacific Oceans, Central Asia and central Africa, then there are plenty of them. They are mainly located near islands, archipelagos, coastal zones of the continents. The dependence of their activity and processes associated with the movement of the earth's crust is universally recognized .
How is a volcanic eruption formed?
How and why volcanoes erupt? The causes of the process lie in the bowels of the Earth. During the accumulation of magma, a large amount of thermal energy is generated. The temperature of magma is quite high, however, it is not able to melt the earth's core, because the crust presses on top of it. If the layers of the earth's crust put less pressure on the magma, the red-hot magma becomes liquid. It is gradually saturated with gases, melts rocks on its way, and thus forgives itself a path to the surface of the earth.
If the volcanic vent is already filled with solidified and solidified lava, then the eruption will not occur until the magnitude of the magma pressure is sufficient to push out this plug. Volcanic eruption is always accompanied by an earthquake. Ashes can be thrown to a height of several tens of kilometers.
Volcanoes are formations resembling the shape of a mountain from which red-hot magma erupts. How is a volcano formed? In the presence of cracks in the earth's crust, red-hot magma erupts to its surface under pressure. The slopes of the volcano are formed as a result of subsidence of rocks, lava, ash near the vent.