An earthquake is a land settlement which is perceived with shaking and tremors. Its origin is mainly due to the collision of tectonic plates, although it can also be caused by other phenomena such as the disruption of underground caves, landslides on the slopes of the mountains, etc.
The outermost layer of the planet earth called lithosphere It is made up of plates that move over a fluid substrate called a "mantle"; such displacement is almost imperceptible, of just a few centimeters a year. The plates tend to rub against each other, creating mountain ranges, volcanoes, ocean trenches, and so-called "fault systems." It is important to note that this phenomenon is the cause that, at present, the continents are separated, since in the past they were integrated into an immense block called Pangea. Observed today, the edges of each continent would fit together, in the form of a "puzzle."
A phenomenon with similar characteristics but of less intensity and magnitude are the so-called “earthquakes”, which, although they produce displacement of plates, do not manage to reach the density of what would be an earthquake. In addition, these can cause, when they occur on underwater surfaces, what we know as a tsunami.
When the earth stirs itself looking for a balance and a readjustment Due to the movement of plates, it is when an earthquake occurs. At that moment energy is released and the movement propagates through waves similar to those of sound, both towards the interior of the earth and towards the outside, causing in the latter case the destruction of the habitable surface, with the dangers that this it implies.
To refer to this phenomenon, scholars use two terms that are intended to be explanatory: hypocenter and epicenter. In the first case, it refers to the place where a break occurs in the earth's crust and where the seismic movement begins; this is precisely where the release of energy occurs. In the second case, it refers to the place on the earth's surface where the energy of the focus is projected.
Furthermore, like most natural phenomena, earthquakes have various measurement scales to precisely determine their intensity. The best known is the famous Ritcher Scale, with a maximum of 10 points, which would be the highest possible magnitude for a phenomenon of this type, and of course, which will have the most serious consequences.
In addition, the so-called "induced earthquakes" are known today, caused for example in areas of exploitation and extraction of hydrocarbons (oil, for example). Of course, the companies that extract these natural resources worry too much about the exploitation of raw materials, but little to anticipate natural disasters, and avoid deaths or serious injuries in the populations surrounding these extraction sites.
At present, it is quite easy to determine which areas are the most prone to disturbances of this type, so in theory it would be possible to take precautionary measures. Unfortunately, many of the most exposed areas coincide with poor regions, so these prevention measures cannot be applied.
The largest earthquakes that occurred during the 20th and 21st centuries have occurred in Indonesia, Japan, Chile, the United States, Mexico, Russia and Portugal.
