NWD/Volcanoes/How are volcanoes formed?
Volcanoes Oct.14.2020

How are volcanoes formed?

volcano plate boundary

In February 1943, in one of the regions of Mexico, people witnessed a rare and amazing spectacle: in the middle of a cornfield, a new volcano was born! In just three months, a conical mountain with a height of 300 meters was formed. As a result, it destroyed two cities and buried the vast territory under a layer of ash and lava. We will tell you about three ways of how volcanoes form and volcanic causes.

So how does the formation of volcanoes proceed?

formation of volcanoes

First of all, we should remember that the temperature in the depths of the Earth rises as we approach the center of the Earth. At a depth of 35-40 km, most of the rocks are in a molten state.

When minerals turn from solid to liquid state, they increase in volume. As a result, new mountain ranges rise at various points of the Earth’s surface. It leads to a decrease in pressure in the thickness of the Earth’s crust, and under the newly formed mountains, huge lakes of magma can appear.

Magma rises, filling the cracks that appeared in the process of mountain formation. When the pressure in the underground lakes becomes too high, the stone vaults bend upwards and form a new volcano.

Formation of the volcanic eruption can be dangerous because a mixture of hot gases, molten rocks, and solid fragments is pushed to the surface from the depths. As they cool down, they form a conical peak of the volcano, with an indentation in the center. In the middle of the crater is an opening – a vent leading to the thickness of the Earth’s crust.

The material ejected through the vent to the surface is mainly a mixture of gases, but a large amount of lava and solid particles in the form of ash erupts with them.

Lava is a magma arising from a volcano but differs from the latter in its physical and chemical properties. Changes occur when the magma rises to the surface, and its temperature and pressure drop dramatically.

Where do volcanoes form?

volcanoes causes

In the area of cities such as New York, London, or Paris, there are no volcanoes, and they are unlikely to appear in the future. However, in some parts of the world, there are several volcanoes in one place.

The Pacific coast of Central America is one of the most active places of volcanic activity in the world. More than two-thirds of active volcanoes are located in this place.

In these places, the Earth’s crust is weak compared to other areas of the globe. A volcano appears in sick parts of the Earth’s crust.

As we already know, the core of the Earth is hot. As the depth increases, so does the temperature. At a depth of 25 km, the temperature is so high that all rocks (here the temperature reaches 1000-1100 ° C) are in the molten state.

When the rock melts, it increases in volume – it needs more space. In some areas of the Earth, new rock systems were formed not so long ago (this means several thousand years ago). Under them and this area, the pressure is lower than in other areas. It is a kind of weak area in the Earth’s crust.

Molten rock, called “magma, penetrates these areas, creating reservoirs of molten rock. Magma rises through cracks formed by the rise of the earth’s rocks. When the pressure in such a reservoir exceeds the forces holding back the magma underground, the molten rock will burst out to form a volcano. The eruption stops with the end of the associated gas emission.

The eruption mainly releases gaseous substances, as well as large amounts of molten rock “lava and solid particles in the form of ash. An eruption is an explosion of gases, but part of the lava turns to dust, and during this process, we see a cloud of black smoke.

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