An earthquake is a shaking of the ground that is produced by internal forces of the planet.
An earthquake is a shaking of the ground produced by forces acting inside the planet . The phenomenon can also be mentioned as an earthquake or earthquake. The word earthquake comes from the Latin terraemotus , while seismo derives from a Greek word that means, precisely, "shaking" .
The shaking of the ground occurs with the collision of tectonic plates , which are fragments of the lithosphere (the most superficial layer of the Earth ) that move as a rigid block, without internal deformation occurring on the asthenosphere (the immediate to the lithosphere, which is between about 100 and about 240 kilometers below the surface).
Another cause of earthquakes is the reorganization of the components of the Earth's crust that releases a large amount of energy , whether due to volcanic processes, slope movements or the elastic potential energy that accumulates with the gradual deformation of the rocks that are found. next to an active fault.
Characteristics of an earthquake
The interior point of the planet where the earthquake takes place is known as the seismic focus or hypocenter . On the other hand, the point on the surface that is vertical to the hypocenter (that is, it is located perpendicular to it) is called the epicenter .
Seismic movements propagate through elastic waves from the hypocenter. There are three main types of seismic waves : primary , longitudinal or P waves (they propagate in the same direction as the vibration of the particles); secondary , transverse or S waves (they propagate perpendicular to the direction of vibration of the particles); and surface waves (they are produced on the Earth's surface as a result of the interaction between primary and secondary waves).
The usual thing is that the tremor of the earthquake is produced by a collision of the tectonic plates
The most violent seismic movements in history
This catastrophe does not contemplate social classes nor does it give much advance notice when it will take place; So much so that its consequences can often be atrocious, devastating entire regions and countries, with the consequent deaths of their inhabitants.
Throughout human history, countless earthquakes have taken place, among the strongest are the following:
- Japan earthquake of March 2011 : it is undoubtedly the strongest in history and reached 8.9 degrees on the Richter scale.
- Valparaíso earthquake (Chile) of July 1730 : one of the most serious suffered in this country which, like the last one that took place in Japan, was followed by a tsunami that devastated several kilometers of the coast. The earthquake reached 8.7 degrees on the Richter scale and the tsunami waves reached 14 meters in altitude.
- Lisbon earthquake (Portugal) of November 1755 : it was an earthquake that almost exceeded 8.7 degrees on the Richter scale ; They were moments of great tension, especially because it was accompanied not only by a tsunami but also by major fires. In total more than 10,000 people died.
- Rat Island earthquake (Alaska) in February 1965 : This earthquake was also followed by a tsunami, with waves up to 10 meters high, which caused damage to the coast. The vestiges of this earthquake were perceived in all the countries of Central America, in Japan and Russia.
- Ecuador earthquake of January 1906 : its relevance is due to the fact that it was a tragedy that affected several affected countries, including Panama, Mexico, Japan and Colombia.
- February 2010 Chile earthquake : It was the strongest earthquake to occur in this country, reaching 8.8 on the Richter scale and claiming the lives of 521 people.