The history of earthquakes in Brazil have recorded aftershocks 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 the geological faults. They occur more frequently in the Northeast region, due to the intense internal movement of the Earth in that location.
Read too: Why are there so many earthquakes in Chile?
Causes of earthquakes in Brazil
In Brazil, the earthquakes are caused by two reasons, the first refers to the wear of tectonic plates, which promotes a slight, almost imperceptible earthquake. The second occurs by the tectonic plate shock, in which there is the epicenter of the earthquake, that is, the place where it is felt most strongly and spreads all over the place. 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 tremble.
Brazil does not suffer intensely from earthquakes, as the country is located in the center of the South American tectonic plate. Thus, the movement of this tectonic plate does not generate 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 plate breaks, that is, by the natural wear of the tectonic plates. These internal movements are capable of making the earth shake and generating a slight earthquake, and are quite common. The exceptions are the strongest tremors, capable of being felt, dropping objects or causing cracks in walls, these, rarely, were seen and felt in Brazil, as they are common in places where there is the collision of plates tectonics.
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 rNortheast 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 sparse, which ranges from 3 m to 20 m in depth. In addition to these factors, the exposure of the rock at various points is considered, which is known as a rock outcrop.
It is known that the formation of these tremors on Brazilian soil comes from rock faults. The total or partial breakage of rocks promotes normal failures, this rocky movement can cause the soil movement, both in greater and lesser intensity, thus causing the earthquake.
See too: Earth layers - representation of the internal structure of our planet
Earthquakes registered in Brazil
Brazil already registers several occurrences of tremors throughout its history, some stronger, some weaker. We will highlight the strongest tremors ever felt and observed in Brazilian territory:
1955 – In Mato Grosso, Serra do Trombador, an earthquake measuring 6.6 on the Richter scale was recorded, without damage to people or cities, as it occurred in sparsely inhabited regions.
1955 – In Espirito Santo, Vitória, there was an earthquake measuring 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, with damage to homes in the area.
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, one child was killed and six people were injured.
2008 – Occurring in São Paulo, Rio Grande do Sul, Santa Catarina, Paraná and Rio de Janeiro, this tremor of scale 5.2 was felt by several people, in different regions of these states, no harm was registered.
In day August 30, 2020 the most recent earthquake on Brazilian soil was recorded by the University's Seismology Laboratory Federal of Rio Grande do Norte, the tremor had 4.6 degrees on the Richter scale, there was no serious material damage or death. The tremor was felt by the residents of the Jiquiriçá Valley and the Recôncavo Baiano region, with the fall of some objects and furniture.
Forecast of earthquakes in Brazil
When it comes to the occurrence of natural phenomena it is hard to predict a new event. When we talk about earthquakes, this imprecision is even greater, as it is a phenomenon that occurs for various reasons, such as tectonism, volcanism or the occurrence of geological faults. In the Brazilian case, the internal dynamics of Tmiss and his movement would explain such an occurrence.
Some geologists are responsible for studies in the area, several universities' seismology laboratories Brazilian companies monitor and record the phenomenon, thus being able to monitor their areas of occurrence and intensity, but no prediction of occurrence.
By Gustavo Henrique Mendonça
Geography teacher
Source: Brazil School - https://brasilescola.uol.com.br/brasil/terremotos-no-brasil.htm
