Large earthquakes reaching 8 points, happen in Chile every 65-85 years.
Santiago, capital of Chile, may become a victim of the powerful earthquake of magnitude 8.3 points on a scale of MMS or above in the near future, warn seismologists who published their forecast in the journal Earth and Planetary Science Letters.
“Powerful determined in the study area in South America, are one of the three effects of dip of the oceanic Nazca plate under the continent at high speed, about 80 millimeters per year. The second consequence of the dip of the Nazca is the compression of rocks and the growth of the Andes, and the third is the formation of Pacific ridge volcanoes. The most powerful earthquake in human history with a magnitude of 9.5, occurred in 1960 in 570 kilometers South of Santiago,” says research geologist David Jacobson from the University of Canterbury (New Zealand).
Cordillera is considered the longest mountain range of Earth, which stretches for 18 thousand kilometers long, and between 9 and 16 kilometres in width. They appeared relatively recently — in the Jurassic period in North America during the late Cretaceous on the southern “half” of the New world as a result of collision of oceanic and continental plates. While there is no generally accepted theory about their origins — as scientists argue about the number of the source of tectonic plates and the nature of their connection.
On the other hand, the consequences of this collision tangible for every citizen West of South America each year occur quite a strong earthquake, resulting in the accumulation of tectonic stresses at the points where plates “scratch” each other” and its release in the form of powerful aftershocks.
Emil Klein from the University of Strasbourg (France) and his colleagues came to the conclusion that the next release of huge portions of energy could occur in the near future in the vicinity of Santiago, capital of Chile. Analyzing the consequences of the powerful earthquake with a magnitude of 8.3 points on a scale of MMS, which occurred in the vicinity of the town of Illapel in September 2015, scientists discovered a disturbing pattern.
It turned out that in virtually all regions in Central Chile, the major aftershocks have occurred fairly regularly, with a frequency of approximately every 60-80 years. For example, Illapel was already struck by a powerful earthquake with a magnitude of 8 or more in 1880 and 1943, and regions to the South of this city was also subjected to strong shocks with the same frequency.
A similar rate of occurrence of earthquakes, as told by Klein and his colleagues suggests that the Nazca plate dives below South America is not such a high velocity, as shown by measurements in other, relatively quiet regions is 6.5 inches, not 8 inches per year. This means in turn that the movement of rocks greatly “hampered” by their friction, with the result that the plate in earthquake-prone regions “behind” every 70 years is approximately 4.5 m from other plots and making up for this gap in the course of earthquakes.
The problem is that in the Central part of this zone is the section length of approximately 300 kilometers, where such shocks have not occurred for over a century, but relatively weak earthquake of 6-7 points on the scale of MMS occur virtually every month. Accordingly, there is a very real and non-zero risk that this tension will be relieved soon. According to scientists, it will be at least 8.3 points on a scale of MMS.
Says Jacobson, a shock with a magnitude of 6.9 last week may be the first Herald of such a catastrophe, but the likelihood of this is quite low, about 10%. In General, according to geologists, the likelihood of a massive earthquake in the vicinity of Santiago this year in 2-3 times above normal, and is about 3%. If it happens, its epicenter will be in the valparaíso region, 100 kilometres from the capital of Chile.
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