Volcanic Eruption (Meaning and Explanation)

We explain what a volcanic eruption is, the types of eruptions, their causes and consequences. Also, security measures.

What is a volcanic eruption?

The volcanic eruption It is a magma emission (mass of molten rocks, liquids and gases) found deep inside the Earth where the temperature is extremely hot. There a strong pressure is generated that pushes the magma towards the surface, seeping through fissures in the ground and volcanoes.

Depending on the composition of the magna, some volcanic eruptions can be explosive and the sediments expelled can reach 20 kilometers in height. An eruption of that magnitude is a rare phenomenon and represents an environmental risk because its effect can alter the climate for years.

Types of volcanic eruption

Volcanic eruptions are differentiated by their type of explosiveness, which depends on factors such as temperature, composition, viscosity and elements dissolved in the magma. Volcanic eruptions can be:

Effusive eruptions Those in which the magma rises through the surface of the volcano in the form of lava or viscous liquid, with a low concentration of gases.
Explosive eruptions Those in which the magma retains a large amount of gases, acquires greater pressure as it rises to the Earth's surface and comes out with great force, in the form of solid fragments called pyroclasts.

In addition, volcanic eruptions are subdivided more carefully, according to the geology from which they emerge, and can be:

Magmatic eruptions They are produced when magma comes to the surface in the form of lava, ash or pumice. Depending on the shape of the volcano, they are called Icelandic, Hawaiian, Vulcanian, Plinean and Fighting eruptions.
Phreatomagmatic eruptions They occur when magma interacts directly with a large mass of water (such as in the ocean, sea or groundwater) so the magnitude of the underwater explosion cannot always be seen from the Earth's surface. Depending on the shape of the volcano, they are called surtseyan, submarine or subglacial eruptions.
Phreatic eruptions They are produced when magma (which is at an extremely hot temperature between 600º and 1100º C) comes into contact with a volume of water that is heated abruptly, generating steam at very high pressure. A large explosion consists of steam, water, ash and sediments, but unlike other types of eruptions, the magma does not usually rise to the Earth's surface.

Causes of volcanic eruptions

phreatic volcanic eruption gas steam — If water comes into contact with magma, the eruption is of steam and sediment.

A volcanic eruption (when magma tries to break out onto the Earth's surface) It happens because tectonic plates move (either because they separate or push each other, causing them to overlap) and the magma from deep begins to rise between the spaces left by the plates.

As the magma rises Bubbles with gas form inside and try to flow to the surface. When the magmatic consistency is thicker, these bubbles cannot flow easily and accumulate more and more pressure, until the explosion occurs.

Another form of volcanic eruption occurs when a mass of underground water comes into contact with magma that is extremely hot. The temperature of the water rises suddenly and an explosion of steam occurs along with remains of sediment, but the magma does not finish coming to the surface.

Consequences of volcanic eruptions

Among the main consequences of volcanic eruptions are:

The transfer of populations Many entire communities are forced to abandon their lands to escape the lava that is capable of destroying everything in its path (in some cases, it has buried entire towns). Once the explosion has stopped, the surrounding environment is fouled with clouds of ash that make visibility and breathing difficult.
Temporary shortages of food and water The hot materials emanating from the volcano mix with the water currents and form a mud that continues to move over the Earth's surface. Fertile soils are ruined and safe water becomes unfit for consumption for a long period of time.
The alteration of the global climate In the case of explosive volcanic eruptions, the diameter of the ash impact affects the Earth's surface and atmosphere, causing lasting changes in climate, even globally. Depending on the composition of the magma, the resulting ash can affect temperatures by making them hotter or colder than usual.

Safety measures in case of volcanic eruption

The most important thing if you live in an area near a volcano is go to local authorities to provide all the necessary information.

In any case, there are some general safety measures to take into account in case you witness a volcanic eruption. For example:

Stay away from areas where there are volcanoes that were detected as active.
If you live near an area with an active volcano, know an evacuation route and have a vehicle that always has a fuel reserve.
Know the emergency plan established by local authorities to know what the agreed evacuation routes and meeting points are.
Have an emergency kit containing: safety glasses or a mask, a flashlight, clothing that protects the extremities and a radio with charged batteries.
If for any reason the area cannot be evacuated, close the doors and windows tightly and block any other openings that communicate with the outside (such as the chimney) to prevent ashes from entering.
Volcanic ash is pulverized rock, extremely harmful. It makes breathing difficult and can also damage engines and machinery, so it is important avoid driving through an ash cloud. If the car is left in the middle of the road, it is essential to move it to the side to avoid accidents.
Ash can make roads slippery, so it is recommended avoid winding routes between the valleys. It is important to drive at a reduced speed to avoid losing control in the event of unforeseen events.
Avoid the areas of depressions in the terrain where the most harmful gases tend to accumulate and can remain even for a long time after the volcanic eruption.

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Volcanoes of Mexico

volcanic eruption popocatepetl mexico — The impact of the volcano on nearby populations depends on the type of eruption.

In Mexico there are about 2,000 volcanoes identified as inactive so they do not represent any danger. However, also there are 12 active volcanoes distributed in the center-southern of the country, such as the Colima and Popocatépetl volcanoes, which are monitored 24 hours a day.

It is estimated that 75% of Mexico's population lives in areas near a volcano. The damage that a volcanic eruption can cause depends on the type of explosion. For example, if it is an eruption of fiery lava, the damage will be greater than if it is an eruption of vapors and ash.

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