The 1755 Lisbon earthquake, also known as the Great Lisbon earthquake, occurred in the Iberian Peninsula and Northwest Africa area on the morning of Saturday, 1 November, 1755 (on the Christian Feast of All Saints); it took place at approximately 09:40 local time.Between History and Periodicity: Printed and Hand-Written News in 17th-Century Portugal In combination with subsequent fires and a tsunami, the earthquake almost completely destroyed Lisbon and adjoining areas. Seismologists estimate the Lisbon earthquake had a magnitude of 7.7 or greater on the moment magnitude scale, with its epicenter in the Atlantic Ocean about west-southwest of Cape St. Vincent, a cape in the Algarve region, and about southwest of Lisbon.
Chronologically, it was the third known large-scale earthquake to hit the city (following those of 1356 and 1531). Estimates place the death toll in Lisbon around 30,000–40,000. A further 10,000 may have died in Morocco.
The earthquake accentuated political tensions in Portugal and profoundly disrupted the Portuguese Empire. The event was widely discussed and dwelt upon by European Enlightenment philosophers, and inspired major developments in theodicy. As the first earthquake studied scientifically for its effects over a large area, it led to the birth of modern seismology and earthquake engineering.
Earthquake and tsunami
The earthquake struck on the morning of 1 November 1755, All Saints' Day. Contemporary reports state that the earthquake lasted from three and a half to six minutes, causing fissures wide in the city center. Survivors rushed to the open space of the docks for safety and watched as the sea receded, revealing a plain of mud littered with lost cargo and shipwrecks. Approximately 40 minutes after the earthquake, a tsunami engulfed the harbor and downtown area, rushing up the Tagus riverViana-Baptista MA, Soares PM. Tsunami propagation along Tagus estuary (Lisbon, Portugal) preliminary results. Science of Tsunami Hazards 2006; 24(5):329 Online PDF. 27 May 2009. "so fast that several people riding on horseback ... were forced to gallop as fast as possible to the upper grounds for fear of being carried away." It was followed by two more waves. Candles lit in homes and churches all around the city for All Saints' Day were knocked over, starting a fire that developed into a firestorm which burned for hours in the city, asphyxiating people up to from the blaze.
Lisbon was not the only Portuguese city affected by the catastrophe. Throughout the south of the country, in particular the Algarve, destruction was widespread. The tsunami destroyed some coastal fortresses in the Algarve and, at lower levels, it razed several houses. Almost all the coastal towns and villages of the Algarve were heavily damaged, except Faro, which was protected by the sandy banks of Ria Formosa. In Lagos, the waves reached the top of the city walls. Other towns in different Portuguese regions, such as Peniche, Cascais, Setúbal and even Covilhã (which is located near the Serra da Estrela mountain range in central inland Portugal) were visibly affected by the earthquake, the tsunami, or both. The shock waves of the earthquake destroyed part of Covilhã's castle walls and its large towers and damaged several other buildings in Cova da Beira, as well as in Salamanca, Spain. In Setúbal, parts of the Fort of São Filipe de Setúbal were damaged.
On the island of Madeira, Funchal and many smaller settlements suffered significant damage. Almost all of the ports in the Azores archipelago suffered most of their destruction from the tsunami, with the sea penetrating about inland. Current and former Portuguese towns in northern Africa were also affected by the earthquake. Places such as Ceuta (ceded by Portugal to Spain in 1668) and Mazagon, where the tsunami hit the coastal fortifications of both towns hard, in some cases going over them and flooding the harbor area. In Spain, the tsunamis swept the Andalusian Atlantic Coast, damaging the city of Cadiz.
Shocks from the earthquake were felt throughout EuropeHistoire de ma vie, Book 2, Ch. XXVI; Casanova himself noted feeling the shocks when he was imprisoned in "The Leads" in Venice and specifically states they were the same ones that destroyed Lisbon as far as Finland and in North Africa, and according to some sources even in GreenlandBrockhaus' Konversations-Lexikon. 14th ed., Leipzig, Berlin and Vienna 1894; Vol. 6, p. 248 and the Caribbean.Lyell, Charles. Principles of Geology. 1830. Vol. 1, chapter 25, p. 439 Online electronic edition. 21 May 2009. Tsunamis as tall as swept along the coast of North Africa, and struck Martinique and Barbados across the Atlantic Ocean. A tsunami hit Cornwall on the southern British coast. Galway, on the west coast of Ireland, was also hit, resulting in partial destruction of the "Spanish Arch" section of the city wall. In County Clare, Aughinish Island was created when a low-lying connection to the mainland was washed away. At Kinsale, several vessels were whirled round in the harbor, and water poured into the marketplace.
In 2015, it was determined that the tsunami waves reached the coast of Brazil, then a colony of Portugal. Letters sent by Brazilian authorities at the time of the earthquake describe damage and destruction caused by gigantic waves.
Although seismologists and geologists have always agreed that the epicenter was in the Atlantic to the west of the Iberian Peninsula, its exact location has been a subject of considerable debate. Early hypotheses had proposed the Gorringe Ridge, about south-west of Lisbon, until simulations showed that a location closer to the shore of Portugal was required to accord with the observed effects of the tsunami. A 1992 seismic reflection survey of the ocean floor along the Azores–Gibraltar Transform Fault detected a thrust fault southwest of Cape St. Vincent, with a dip-slip throw of more than . This structure may have created the primary tectonic event.Zitellini N. et al., The tectonic source of the 1755 Lisbon earthquake and tsunami. Annali di Geofisica 1999; 42(1): 49. Online PDF. 27 May 2009.
Casualties and damage
Economic historian Álvaro Pereira estimated that of Lisbon's population at the time of approximately 200,000 people, 30,000–40,000 were killed. Another 10,000 may have died in Morocco. A 2009 study of contemporary reports relating to the 1 November event found them vague and difficult to separate from reports of another local series of earthquakes on 18–19 November.Blanc P.-L. (2009) Earthquakes and tsunami in November 1755 in Morocco: a different reading of contemporaneous documentary sources. Nat. Hazards Earth Syst. Sci. 2009; 9: 725–738. Pereira estimated the total death toll in Portugal, Spain and Morocco from the earthquake and the resulting fires and tsunami at 40,000 to 50,000 people.Pereira (2006), pp. 8–9, 33–9921.
85% of Lisbon's buildings were destroyed, including famous palaces and libraries, as well as most examples of Portugal's distinctive 16th-century Manueline architecture. Several buildings that had suffered little earthquake damage were destroyed by the subsequent fire. The new Lisbon opera house (the "Ópera do Tejo"), opened seven months before, burned to the ground. The Royal Ribeira Palace, which stood just beside the Tagus river in the modern square Praça do Comércio, was destroyed by the earthquake and tsunami. Inside, the 70,000-volume royal library as well as hundreds of works of art, including paintings by Titian, Rubens, and Correggio, were lost. The royal archives disappeared together with detailed historical records of explorations by Vasco da Gama and other early navigators. The palace of Henrique de Meneses, 3rd Marquis of Louriçal, which housed 18,000 books, was also destroyed. The earthquake damaged several major churches in Lisbon, namely Lisbon Cathedral, St Paul's Cathedral, Santa Catarina, São Vicente de Fora, and the Church of Nossa Senhora da Conceição Velha. The Royal Hospital of All Saints (the largest public hospital at the time) in the Rossio square was consumed by fire and hundreds of patients burned to death. The tomb of national hero Nuno Álvares Pereira was also lost. Visitors to Lisbon may still walk the ruins of the Carmo Convent, which were preserved to remind Lisboners of the destruction. Most of the documentation of the 1722 Algarve earthquake sent to Lisbon for archiving became lost after the fire that followed the 1755 earthquake.
Relief and reconstruction efforts
The royal family escaped unharmed from the catastrophe: King Joseph I and the court had left the city, after attending Mass at sunrise, fulfilling the wish of one of the king's daughters to spend the holiday away from Lisbon. After the catastrophe, Joseph I developed a fear of living within walls, and the court was accommodated in a huge complex of tents and pavilions in the hills of Ajuda, then on the outskirts of Lisbon. The king's claustrophobia never waned, and it was only after Joseph's death that his daughter Queen Maria I began building the royal Palace of Ajuda, which still stands on the site of the old tented camp. Like the king, the prime minister, the 1st Marquis of Pombal, survived the earthquake. When asked what was to be done, Pombal reportedly replied, "Bury the dead and heal the living", Kendrick writes that the remark is apocryphal and is attributed to other sources in anti-Pombal literature. and set about organizing relief and rehabilitation efforts. Firefighters were sent to extinguish the raging flames, and teams of workers and ordinary citizens were ordered to remove the thousands of corpses before disease could spread. Contrary to custom and against the wishes of the Church, many corpses were loaded onto barges and buried at sea beyond the mouth of the Tagus. To prevent disorder in the ruined city, the Portuguese Army was deployed and gallows were constructed at high points around the city to deter looters; more than thirty people were publicly executed.Gunn (2008), p. 77. The army prevented many able-bodied citizens from fleeing, pressing them into relief and reconstruction work.
A project proposed that a new royal palace be built in Campo de Ourique as the new royal residence in 1760, but was later abandoned due to a lack of priority or interest in a palace being built in the Campo de Ourique neighborhood of Lisbon.
The king and the prime minister immediately launched efforts to rebuild the city. On 4 December 1755, a little more than a month after the earthquake, Manuel da Maia, chief engineer to the realm, presented his plans for the rebuilding of Lisbon. Maia presented four options, from abandoning Lisbon to building a completely new city. The first and cheapest plan was to rebuild the old city using recycled materials. The second and third plans proposed widening certain streets. The fourth option boldly proposed razing the entire Baixa quarter and "laying out new streets without restraint". This last option was chosen by the king and his minister.Shrady, The Last Day pp. 152–155.
In less than a year, the city was cleared of debris. Keen to have a new and perfectly ordered city, the king commissioned the construction of big squares, rectilinear, large avenues and widened streetsthe new mottos of Lisbon.
The Pombaline buildings are among the earliest seismically protected constructions in Europe. Small wooden models were built for testing, and earthquakes were simulated by marching troops around them. Lisbon's "new" Lower Town, known today as the Pombaline Lower Town (Baixa Pombalina), is one of the city's famed attractions. Sections of other Portuguese cities, such as the Vila Real de Santo António in Algarve, were also rebuilt along Pombaline principles.