Introducción a los sismos (Terremotos)

Tremors or earthquakes (larger earthquakes), also known as telluric movements due to their relationship with the Earth as a planet, are the result of rocks breaking, suddenly releasing energy at a certain point in the earth’s crust. This energy is transmitted in the form of seismic waves, which propagate away from their point of origin, in the same way that a pond is made by waves away from the point where we throw a stone. Hypocenter is called the place under the earth where the earthquake is generated, and its epicenter projection to the surface. [1]

The earthquake is one of the natural phenomena that has caused more terror and more damage to humanity. The struggle of man to achieve his control has been hard, however today there is a lot of information that although they do not avoid them completely, will manage to prevent incalculable damages. Earthquakes are caused by (i) volcanic activity although they are not so common, (ii) the sinking of underground cavities that do not release much energy so they are not of great importance or (iii) the tectonic displacements of the earth’s crust, According to the researchers, they agree that the continents are continually colliding with each other and that these changes in position are the cause of the largest earthquakes in the world. In the places where these movements occur, many cubic kilometers of rock are drastically deformed, accumulating the energy as in a tensioned spring. [2]

Many wonder if it will be possible to predict earthquakes. “We do not know precisely the parameters that interact to cause an earthquake and temporarily quantify the energy that accumulates in the terrestrial tectonic plates and when the rock is going to break to release that energy in an elastic way” said Mario Araujo, chief of the Department of Seismological Investigations of the National Seismic Prevention Institute of Argentina, in 2010 in an interview for the digital newspaper La Nación. [3]

Currently there is no method capable of detecting where and when an earthquake will occur due to the non-linear and quite chaotic behavior of seismic movements. Emilio Carreño, director of the National Seismic Network of Spain explains that “When an earthquake occurs, many other phenomena precede it but it has been proven that not all of them always occur. At present, it is impossible to measure so many parameters at the same time without the guarantee that they will be produced, hence the difficulty to detect them in advance “. In the same way the researcher of the CSIS (Superior Council of Scientific Investigations of Spain), María José Jiménez, “It is possible to forecast where they will be more severe but not to predict them individually. What we can do is minimize its effects to the maximum by developing systems for rapid response. ” [4]

For a long time scientists have been working on the development of new technologies and mechanisms to adjust the prediction of eventual earthquakes but we are still far from predicting an earthquake individually. An article published in Prensa Libre on September 28, 2003, mentions that the Chinese have used experimental farms where animals detect low density vibrations that precede tremors, but this method has produced few results, it seems that the possibility of Predicting an earthquake is far away. NASA works on satellite-based technologies that indicate seismic activity but it could take years before developing an effective system. Thus, the only way to prevent damage is to build with seismic-resistant materials and avoid building in areas of seismic risk. To that end, there are currently maps that provide engineers and architects with information on places where it is possible to build following certain parameters so that buildings can withstand seismic movements. (Free Press, International Writing)

It is common to hear that earthquakes are natural catastrophes in relation to which “little or nothing can be done” referring to the devastating effects that an earthquake can cause in just a few seconds. Nothing could be more wrong. The vast majority of the consequences of earthquakes are not directly “natural”. Citing the example that Raimundo Delgado uses in the first chapter of the book “Sismos y edificios” (2008):

“For example, what happens to someone who is in the middle of a football field during a violent earthquake? You may eventually lose your balance and fall to the ground, but being away from constructions or objects that may fall on you probably nothing else will happen to you. What causes most of the victims and economic losses during violent earthquakes are the damages and collapses of buildings, infrastructure networks and other elements, they are not properly earthquakes. “ [5]

Which means that seismic catastrophes are not natural catastrophes but catastrophes caused by constructions built by man, however, it is often confused the phenomenon that gives rise to the event with the consequences that the hand of man promotes. However, the consequences are the result of the action of man, means that it is possible to significantly reduce these same consequences by the same hand of man through constructions adapted to these events, more resistant for the safety of people.


[1] Rivadeneira, F., Segovia, M., Alvarado, A., Egred, J., Troncoso, L., Vaca, S. y Yepes, H. Breves fundamentos sobre los terremotos en el Ecuador. Instituto Geofísico de la Escuela Politécnica Nacional. Corporación Editora Nacional. Quito, Ecuador. Noviembre 2007.

[2] Müncener Rückversicherungs-Gesellschaft. Terremotos. Munich, 1974.

[3] Ingrassia, V. (15 de enero del 2010). ¿Por qué la ciencia aún no puede predecir un terremoto? La Nación, periódico digital argentino. Recuperado de Acceso: miércoles 06 de septiembre del 2017.

[4] Guerrero, T. (13 de enero del 2010). ¿Por qué es tan difícil predecir un terremoto? El Mundo, periódico digital español. Recuperado de Acceso: miércoles 06 de septiembre del 2017.

[5] Raimundo Delgado, Mário Lopes. Sismos e Edifícios, Primeira Edição. Capítulo I: Breve referência à história da Engenharia Sísmica, pp1. Portugal, julho 2008.