2023-08-18 16:00:00
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The radio program you are listening to has just been interrupted by breaking news: “an earthquake measuring 5.7 on the Richter scale has caused chaos on the other side of the world.”
A magnitude of 5.7 sounds serious, especially considering that the Richter scale was designed to determine the forces involved in an earthquake with a magnitude between 2.0 and 6.9 and produced between the first 400 kilometers of depth, but It is very possible that, even if you sense it, you do not fully understand what they mean.
Video: The devastating earthquake in Türkiye and Syria
To shed light on this question, we will say that the Richter seismological scale, also known as the local magnitude scale, is a logarithmic scale used to quantify the energy released by an earthquake. It was established by the seismologist Charles Francis Richter together with the also German-American seismologist Beno Gutenberg in the year 1935.
The keys to the earthquake in Türkiye and Syria
The key to the Richter scale of earthquakes
One of the most important things to take into account in this scale is precisely the way in which it is adjectived. Contrary to linear scales, in which each magnitude has the same length as the previous one, that is, it represents the same value, On logarithmic scales, each successive magnitude has a much larger value than the previous magnitude, which in the case of the Richter scale is 100. That is, if we have 2 earthquakes with a magnitude of 3 and 6 respectively, the energy released by the second earthquake will not be twice that of the first, but 1,000,000 times higher.
Video: All earthquakes from 2001 to 2015 in less than 4 minutes
Continuing with the example of the radio, it is common that instead of “an earthquake of magnitude 5.7 on the Richter scale”, some announcers refer to the event using the term “degree”, that is, “an earthquake of 5, 7 degrees on the Richter scale. The Richter scale is not expressed in degrees, but this confusion is due to the fact that there are other scales that, in the same way as the Richter, quantify the intensity of earthquakes.
Designed to measure small earthquakes
In fact, the Richter scale was designed to measure relatively weak earthquakes, as we said a few lines ago, between magnitudes 2.0 and 6.9. In addition, another problem with this scale is that it is difficult to relate it to the physical characteristics of the origin of the earthquake, which is why, at the beginning of the 21st century, many seismologists considered it obsolete and replaced it with a more appropriate scale known as the seismic scale of moment magnitude.
The seismic scale of moment magnitude is based on the measurement of the total energy that is released in an earthquake. It was introduced in 1979 by Thomas C. Hanks y Hiroo Kanamori as the successor of the Richter seismological scale, and has the advantages that coincides and continues with the parameters of the Richter seismological scalebut unlike its predecessor, it is used to weight the energy released in earthquakes of magnitudes greater than 6.9.
The mathematics of the Mexico earthquake
The largest earthquake in history was the one that took place on May 22, 1960 in the city of Valdivia, in Chile, which reached a moment magnitude of 9.6. Despite knowing that it is the largest earthquake that has ever occurred on Earth, perhaps a number like this still does not tell you anything, so below we show you a table that describes the typical effects of earthquakes of various magnitudes. At this point, it should be remembered that the Richter and moment magnitude scales coincide up to values of 6.9, and it should also be taken into account that these values must be taken with extreme caution, since the possible effects of an earthquake do not depend exclusively on its magnitude, but also other parameters such as the distance from the epicenter, the depth at which it occurs and the geological conditions of the place.
Magnitude less than 2: microseisms. They are not noticeable. About 8,000 are produced a day.Magnitude 2.0 – 2.9: minor earthquakes. They are not usually noticeable. About 1,000 are produced a day.Magnitude 3.0 – 3.9: minor earthquakes. Often noticeable; they rarely cause damage. 49,000 are produced a year.Magnitude 4.0 – 4.9: light earthquakes. It causes the movement of objects in the houses, but they rarely cause damage. 6,200 are produced a year.Magnitude 5.0 – 5.9: moderate earthquakes. It can cause major damage in weak or poorly built buildings. In well-designed buildings the damage is slight. 800 a year are produced.Magnitude 6.0 – 6.9: strong earthquakes. They can destroy populated areas up to 100 miles around. 120 are produced per year.Magnitude 7.0 – 7.9: major earthquakes. They can cause serious damage over large areas. 18 are produced per year.Magnitude 8.0 – 8.9: epic or catastrophic earthquakes. They can cause serious damage in areas of several hundred kilometers. They occur from 1 to 3 per year.Magnitude 9.0 – 9.9: epic or catastrophic earthquakes. Devastating, they can affect areas of thousands of kilometers. They occur between 1 and 2 every 20 years.magnitude greater than 10: apocalyptic or legendary earthquakes. Never recorded in Earth history. Estimated for the shock of a rocky meteorite 2 kilometers in diameter that impacts our planet at 25,000 kilometers per hour.Magnitude 12: It would cause the Earth to fracture in the center.Magnitude 13: Equivalent to the energy released by the meteorite that killed the dinosaurs.Magnitude 25: Equivalent to the impact of Tea against the Earth, the hypothetical planetoid that caused the formation of the Moon.Magnitude 32: Earthquake similar to those on the solar surface.
Video: All the earthquakes of the beginning of the century in a single video
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