The history of earthquakes in Brazil have already recorded tremors of more than six degrees on the Richter scale, which is considered a high level and can cause damage to property and health. Currently, there are no future projections of when new tremors may occur in our territory.
These phenomena can be caused by volcanism, movement of tectonic plates and geological faults. In Brazil, the most common case is geological faults. They occur more frequently in the Northeast region, due to the intense internal movement of the Earth in that locality.
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Causes of earthquakes in Brazil
In Brazil, earthquakes are caused by two reasons, the first refers to the wear of tectonic plates, which causes a slight tremor of the earth, almost imperceptible. The second occurs by collision of tectonic plates, where there is the epicenter of the earthquake, that is, the place where it is felt most strongly and propagates everywhere. The plate contact area is not always the epicenter of the tremor.
The following image shows the earthquake’s epicenter and the propagation of energy waves through the earth, causing the areas it hits to shake.
Brazil does not suffer intensely from the action of earthquakes, as the country is located in the center of the South American tectonic plate. In this way, the movement of this tectonic plate does not generate a convergent movement in our territory, that is, there are no strong earthquakes in Brazil.
The tremors felt in our country are formed by geological faults, which are fractures or breaks in the plates, that is, by the natural erosion of tectonic plates. These internal movements are capable of making the earth tremble and of generating a slight seismic shock, being quite common. The exceptions are the strongest tremors, capable of being felt, of knocking down objects or causing cracks in walls, these, rarely, have been seen and felt in Brazil, as they are common in places where there is a clash of tectonic plates.
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Where do earthquakes occur in Brazil?
Earthquakes in Brazil are not common or recurrent, however, when they occur, they are located in the same location, in the Northeast region, more precisely in the states of Ceará, Pernambuco and Rio Grande do Norte. Scholars understand that the recurrence in these regions is due to the geology of the place.
The region is formed by several fragments of ancient rocks, and there are several geological faults in these rock fragments. There is also your layer of ground little extensive, which varies from 3 m to 20 m in depth. In addition to these factors, the exposure of the rock at several points is considered, which is known as rocky outcrop.
It is known that the formation of these tremors on Brazilian soil comes from rocky faults. The total or partial breaking of the rocks promotes normal faults, this rocky movement can cause the movement of the ground, both in greater intensity and in lesser intensity, thus causing the earthquake.
See also: Layers of the Earth – representation of the internal structure of our planet
Earthquakes recorded in Brazil
Brazil already registers several occurrences of tremors throughout its history, some stronger, some weaker. Let’s highlight the strongest tremors ever felt and observed in Brazilian territory:
1955 – In Mato Grosso, Serra do Trombador, an earthquake of magnitude 6.6 on the Richter scale was recorded, without damage to people or cities, as it occurred in sparsely populated regions.
1955 – In Espírito Santo, in Vitória, there was an earthquake with a scale of 6.3 degrees, at the time buildings and houses shook. There were no deaths, injuries or major damage.
1980 – In Ceará, in Pacajus, metropolitan region of Fortaleza, there were tremors of 5.2 on the Richter scale, they were also felt in the capital.
1986 – In Rio Grande do Norte, in the city of João Câmara, there was an earthquake measuring 5.1 on the Richter scale, causing damage to homes in the area.
Effects on homes promoted by the action of earthquakes.
2007 – On the border between Acre and Amazonas, there was a tremor of 6.1 degrees. The tremor did not cause any damage, it was only felt in nearby regions.
2007 – In Minas Gerais, in the city of Itacarambi, a tremor of 4.9 on the Richter scale was recorded. Even with a scale considered small, there was the death of a child and six people were injured.
2008 – Occurring in São Paulo, Rio Grande do Sul, Santa Catarina, Paraná and Rio de Janeiro, this 5.2 scale tremor was felt by several people, in several regions of these states, no damage was registered.
In day August 30, 2020 The most recent earthquake on Brazilian soil was recorded by the Seismology Laboratory of the Federal University of Rio Grande do Norte, the tremor had a 4.6 degree on the Richter scale, there was no serious material damage or death. The tremor was felt by residents of the Jiquiriçá Valley and the Recôncavo Baiano regionwith the fall of some objects and furniture.
earthquake forecast in Brazil
When it comes to the occurrence of natural phenomena it is difficult to predict a new event. When we talk about earthquakes, this inaccuracy is even greater, as it is a phenomenon that occurs for various reasons, such as tectonics, volcanism or the occurrence of geological faults. In the Brazilian case, the internal dynamics of the Earth and its movement would explain such an occurrence.
Some geologists are responsible for studies in the area, several seismology laboratories at Brazilian universities monitor and record the phenomenon, thus being able to monitor its areas of occurrence and intensity, but no prediction of occurrence.