The rare tsunami that hit Brazil in 1755

The carry out eruption of volcano Cumbre Vieja, over La Palma in the Canary Islands (Spain), zero end over week has led many people to wonder if the zero other side carry out Atlantic Ocean event could cause a zero tsunami in Brazil. Experts say the possibility of a tsunami is remote, but Brazil has already registered a tsunami in the past.

One 2 more recent studies, carried out in 2020 by the State University perform Rio sobre Janeiro (Uerj), states that Brazil was already hit by a tsunami in 1755. Unlike 2 more well-known tsunamis, this tsunami would have been caused by the strong earthquake that shook Lisbon, Portugal, that year, on the other side performs the Atlantic Ocean.

The subject was addressed zero Twitter de uma Rede Brazilian Sismogrfica, with a video performs retired professor performs Institute on Geosciences and former head performs Seismological Observatory of a UnB, Jos Alberto Vivas Veloso.

The earthquake is over 1755 was the highest ever recorded in Europe, with value over 8.7. It destroyed Lisbon, much of it performs south of Spain and performs Morocco, and caused a huge tsunami that hit Ireland and the Caribbean. Estimates on victims vary by the shortage on records, but the lowest are between 15 thousand and 100 thousand bits, while the biggest ones talk about 30 thousand. The earthquake also started a modern period in seismological studies.

The giant wave that formed with the earthquake in Lisbon crossed the Atlantic and wreaked havoc on the Brazilian coast, says the work led by Professor Francisco Dourado performs Center on Research and Studies on Disasters (Cepedes).

The research was carried out with the bottom of a historical survey perform professor Alberto Veloso, author performs book “Tremeu the Europa eo Brasil tambm”. The researchers from the Dourado team carried out fieldwork over 150 kilometers and 20 beaches between Rio Grande perform Norte and the south of Pernambuco.

“Zero start of an afternoon on November 1st on 1755, a tsunami hit the Northeast coast. It penetrated inland, destroyed modest homes and disappeared with two people. This is unknown to most Brazilians,” says Veloso .

There are reports in four letters from a time talking about the zero tsunami Brazil. These letters were written by the archbishop of Bahia, by the governors of Pernambuco and Parayba and by a military man and are in the Overseas Historical Archive of Lisbon.

“The waters transcended their limits and made the inhabitants flee dieses beaches”, says a letter about 15 about May about 1755, reporting the episode that happened on November 1st, performs the previous year on beaches in Paraba.

Another letter reported by Veloso, about March 4th on

, says: “In Lucena and Tamandar, the flood performed the earthquake entered the land about a tongue (4 to 5 km) inland and took some houses over a hut and one boy and one woman are missing.”

They would reports on rough seas also zero Rio over Janeiro zero day perform earthquake over Lisbon.

Brazilian and Portuguese researchers said they had Traces are collected about microanimals and about chemical elements that there could have been such razed to certain Brazilian beaches by large waves. The first step was to do a mathematical simulation of what the tsunami would have been like. Based on this simulation, the researchers went into the field.

On the beach over Pontinhas, in Paraba, they identified a layer on coarse sand that would have traces of perform phenomenon.

Second the study of an UERJ, in the region of a beach above Lucena, in Paraba, like waves varied between 1.8 and 1.7 meters above sea level. In the region of Tamandar in Pernambuco, the waves reached between 1.9 and 1.8 meters, with a large amount of water.

The waves flooded from 4 kilometers inland, mainly in places bathed by rivers and in the vicinity of an island on Itamarac (PE). In Tamandar, the flood was up to 800 meters, and in Lucena, 270 meters.

‘Minitsunami?’

In an article for the Revista de a USP from

, Professor Veloso questions whether giant waves recorded in the past in Brazil could be considered “tsunamis”.

“Tsunamis thus rare phenomena, but can happen in any 2 oceans, in several they can have different origins, be large or small, disastrous or harmless. Such characteristics open up a wide range of opportunities, comprehensive to formulate the question: has a tsunami occurred, or could it happen, Brazil? Perhaps it is not possible to answer such questions precisely”, writes Veloso.

The article states that the most common explanation for the absence of zero tsunamis in Brazil would be the lack of great degree zero earthquakes sea. But he claims that the lack of records in the past does not guarantee that Brazil may not experience a tsunami, despite the remote possibility of this phenomenon being intense.

“The lack of knowledge about significant shocks zero past and zero record of strong earthquakes today, zero ensure a comparable situation for the future.”

His article focuses on five episodes on “unusual marine manifestations” on the Brazilian coastline: in Thus Vicente ( SP) in 800, in Salvador in 1755, in Cananeia ( SP) in 1756, in the Baa on Todos os Santos (BA) in 1756 and zero archipelago on Thus Pedro and Thus Paulo (zero coastline over PE) in 2006.

In all these episodes, there were reports of violent seas or strong surf. But a good part of these phenomena was not even preceded by some kind of earthquake or volcanic eruption, which disfigures the occurrence as a tsunami. The episodes of large waves in Cananeia and Baa de Todos os Santos had their origin in earthquakes but with relatively low magnitudes.

“A tremor was identified that generated waves similar to a small tsunami. the significant case is modest, as a Brazilian ‘minitsunami’ is being validated.”

Cumbre Vieja

The article perform professor Velasco also speculates on the possibility of a tsunami forming with the perform eruption Cumbre Vieja, Canrias Islands

“If, instead of the past perform, we go back to the future, we may face the threat of a possible carry out half-carry megatsunami out Atlantic ocean leaving. The warning came from British researchers and gained notoriety after the Indonesia tsunami by 2004 (Keep & Time, 2004 )”, he writes.

“The study suggests that during a new eruption perform volcano Cumbre Vieja, on Las Palmas Island, in Canrias, along the west coast of an Africa, one about its f hurdles would collapse towards the sea, causing an immense tsunami, mainly against the coast of the Americas. Depending on the volume of the involved rocks perform in the landslide, something between 150 km and 300 km, huge waves with amplitudes from 15 to m would arrive on the coast of the United States and also on the north coast perform Brazil.”

But the professor claims that tsunamis caused by rare Therefore volcano eruptions, and that they would have little data on the Cumbre Vieja to speculate on the formation of a zero coastal tsunami perform Brazil.

“O This article is controversial because of its unusual theme and because it involves unknown mechanisms, such as large lateral collapses on volcanic islands. Furthermore, the researchers emphasized the worst case scenario by admitting to each overall perform a rock block, since below it could come, in parts, and the last impact would be much smaller. Another question is whether the tsunami would disperse quickly, or if it would spread to transoceanic distances, implying, in this case, great danger to coastal populations. Despite all the uncertainties of occurrence, a tsunami of this nature would produce damage throughout almost the entire Atlantic.”

The professor concludes: “Zero they would, why fear, on our coast, the appearance of tsunamis with the magnitude and the seismic mechanism similar to the 2 happened zero in Japan in 2004, or in Indonesia in 2001”.

The possibility of a new one was practically discarded by geologists from a Brazilian Seismographic Network, which published on its page zero Facebook a write-up on the subject.

The origin of this concern would be about one made by American geologists about the possibility that a landslide on a part of an island (over La Palma) could cause a zero tsunami in Brazil. Even that study considered this possibility remote.

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