Everyone has the image of an earthquake in mind. We have seen them in the cinema and on television, where they have found their way through fiction or on the news channels when they take place in different countries. Earthquakes are associated with the movement of the ground, which means that everything around us shakes and that, in some cases, there is great devastation and personal damage.
However, what exactly are earthquakes? How many types are there and what do they imply? If you want to find out, keep reading a HOWTO and we’ll tell you about it in this article about what are earthquakes, their causes, types and consequences.
What are earthquakes
The word earthquake comes from Latin and literally means “Earth movement”. In fact, it is in their origin that they are associated with ground shaking, whether of one type or another. Usually any earth shaking it can be considered as an earthquake. However, in general, it is said that only those earth movements that reach a certain magnitude are earthquakes.
An example of this can be found during the circulation of metro trains in some cities. It is common for the ground to shake for a few moments as the underground convoys pass, and then resume its normal tranquility. In this case, although it is true that we are facing a “movement of the earth”, it is not usually classified as an earthquake.
Why do earthquakes happen
The causes of earthquakes can be of two types: natural or artificial
Natural causes of earthquakes
They are the consequence of plate tectonics activity of the planet itself. Planet Earth is made up of a solid core, which is followed by a next layer called the mantle, which is liquid. This layer is composed mainly of magma which, being liquid, is in motion. Finally, there is the final layer, the crust, made up of various plates called tectonic plates that float on this liquid mantle. When mantle activity moves the tectonic plates that make up the surface, the earth shakes, causing natural earthquakes. As it cannot be otherwise, the areas where the faults are found (that is, the separations between the tectonic plates), register greater seismic activity because the movements of the mantle cause these plates to collide with each other.
Man-made causes of earthquakes
They are the consequence of human activity. In these cases, the ground tremors do not come from the inner activity of the planet, but are the consequence of human actions that can cause the earth to shake just as it does when earthquakes occur naturally. An example of this type of earthquake would be found during the detonation of an atomic bomb, which in addition to the devastation caused by the bomb itself and the consequent radiation, would also involve a shaking of the ground that could clearly be classified as an earthquake.
Types of earthquakes
One of the ways of cataloging earthquakes would be according to their nature (natural or artificial), as we have already seen. However, the most common is that the typology of earthquakes is associated with the energy released. That is, the force with which they shake the earth and which, consequently, is directly associated with its destructive power.
One of the most common ways of cataloging the types of earthquakes is using the Richter scale. This scale sets the strength of earthquakes from 0 to 10 force points, establishing up to 8 possible types of earthquakes. These are the different types of earthquakes that exist:
- Earthquakes of less than 2 points: these are the so-called microseisms, barely perceptible.
- Earthquakes from 2 to 3.9 points: These are called minor earthquakes, since they rarely cause damage.
- Earthquakes from 4 to 4.9 points: these are called light earthquakes; They cause little damage that is usually limited to the movement of objects in the rooms.
- Earthquakes from 5 to 5.9 points: these types of earthquakes are called moderate, as they can cause damage to weak structures.
- Earthquakes from 6 to 6.9 points: they are the strong ones and, in this case, they are earthquakes that can destroy populated areas and buildings.
- Earthquakes from 7 to 7.9 points: these are the largest earthquakes, they cause serious damage in populated areas.
- Earthquakes from 8 to 9.9 points: these types of earthquakes are called cataclysms, since they are the most devastating known and can cause damage in areas of hundreds of kilometers.
- Earthquakes of more than 10 points: these are the so-called legendary or apocalyptic earthquakes, none of them have ever been recorded.
For more information on this system, take a look at this article on the Difference between the Richter and Mercalli scale.
Consequences of earthquakes
The consequences of earthquakes always depend on their own strength and other factors. However, broadly speaking, we can mention two main consequences.
Consequences for living beings
It is about consequences that cause damage to human populations, animals and other living beings due to the destruction that is associated with these phenomena. As we have seen, depending on the strength they have and the associated points on the Richter scale, they will be more or less destructive, but an entire area can be destroyed in a short time and it can become irrecoverable or difficult to recover.
Consequences on geographical evolution
On the other hand, earthquakes have the consequence of changing the planet’s landscape. Due to the activity of earthquakes, tectonic plates move, a phenomenon known as plate tectonic drift. This, over millions of years, can make the orography of our planet are in constant change.
In the video below you can learn more about what earthquakes are. If this information has been useful to you and you want to discover more details about other phenomena and natural disasters, we recommend the following articles:
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