The volcanoes they are conduits that are in the Earth, and that communicate the terrestrial surface with the hottest and inner layers of the planet.
It is one of the surface and subsurface manifestations of the internal energy of the planet, and their main characteristic is the possibility of generating volcanic activity, represented by the rise of gases and fluids from the interior of the earth to the earth’s crust.
Dormant, active and extinct volcanoes
The process by which the volcano can communicate with the outside is called eruption, and can include events of very strong destructions for the society that lives around the volcano.
- Active volcanos. They are those that occasionally become active, and science has not yet been able to reliably predict these eruptions. Although there are a huge number of volcanoes on the planet, only 500 belong to the group of active ones.
- Dormant volcanoes. They are those that maintain certain signs of activity, but for a very long period (25,000 years) have not erupted.
- Extinct volcanoes. They are those that were not active for periods, and show no signs of being able to reactivate.
Structure and parts of the volcano
The temperature and the Pressure of the volcanoes increases according to the deepest position, and temperatures of around 5000 ° C can be reported, which gives the typical characteristic of volcanoes to be very hot.
- The hottest point of the volcano is the core, where the materials behave like a liquid.
- The mantle It is the intermediate part, and presents temperatures above 1000 ° C with a semi-rigid behavior.
- Finally, it is called Cortex to the outer layer that is in contact with the environment.
Beyond these three sectors, the different parts of the volcano’s structure are distinguished:
- Volcanic cone. Formed by the pressure of magma as it rises.
- Magmatic chamber. Bag found inside the earth, made up of minerals and rocks in a liquid state.
- Crater. Mouth through which the rash can occur.
- Fumarole. Gas emissions in lavas.
- Wash. Magma that rises reaching the surface.
- Magma. A mixture of solids, liquids and gas that, when they rise, give rise to lava.
How are volcanoes formed?
The primary reason that founds the existence of volcanoes is the division into fourteen plates that has the most superficial layer of the earth: African, Antarctic, Arabian, Australian, Caribbean, Scottish, Eurasian, Philippine, Indian, Juan de Fuca, Nazca, Pacific, North American and South American.
Among all these plates make up the Earth crust, and on the edges of them the external manifestations of the inner activity of the earth are concentrated, especially volcanoes and earthquakes. Based on this, volcanoes can have three origins:
- It can happen that the collision of plates deposit one below another until reaching a depth where it dehydrates or melts: in this case magma is formed that rises through the fissures and an eruption occurs, as in the volcanoes of Peru. .
- The convective currents of the earth influence the generation of plumes of ascending magma, which give rise to volcanoes of a basic nature (called basalts). These are the hot spot volcanoes.
- Those areas where tectonic plates diverge from one another are called divergent boundaries, and they cause the oceanic crust to stretch and separate, forming a weak zone. On that side it is possible for magma to emerge, generating the upper mantle of a volcano, as it happens on the ridge of the Atlantic.