The 1755 Lisbon earthquake took place on November 1, 1755, at 9:20 in the morning. It was one of the most destructive and deadly earthquakes in history, killing well over 100,000 people. The quake was followed by a tsunami and fire, resulting in the near total destruction of Lisbon. The earthquake accelerated political tensions in Portugal and profoundly disrupted the country's 18th century colonial ambitions. The event was widely discussed by European Enlightenment philosophers, and inspired major developments in theodicy and in the philosophy of the sublime. The first to be studied scientifically for its effects over a large area, the quake signalled the birth of modern seismology. Geologists today estimate the Lisbon earthquake approached magnitude 9 on the Richter scale, with an epicenter in the Atlantic Ocean about 200 km west-southwest of Cape St. Vincent.
The earthquake struck on the morning of November 1, the All Saints Day Catholic holiday. Contemporary reports state that the earthquake lasted between three-and-a-half and six minutes, causing gigantic fissures five meters wide to rip apart the city center. The survivors rushed to the open space of the docks for safety and watched as the water receded, revealing a sea floor littered by lost cargo and old shipwrecks. Several tens of minutes after the earthquake, an enormous tsunami engulfed the harbor and downtown, rushing up the Tagus river. It was followed by two more waves. In the areas unaffected by the tsunami, fire quickly broke out, and flames raged for five days.
Lisbon was not the only Portuguese city affected by the catastrophe. Throughout the south of the country, in particular the Algarve, destruction was generalized. The shockwaves of the earthquake were felt throughout Europe as far as Finland and North Africa. Tsunamis up to twenty meters in height swept the coast of North Africa, and struck Martinique and Barbados across the Atlantic. A three meter tsunami hit the Southern English coast.
Of a Lisbon population of 275,000, up to 90,000 were killed. Another 10,000 were killed across the Mediterranean in Morocco. Eighty-five percent of Lisbon's buildings were destroyed, including its famous palaces and libraries, as well as most examples of Portugal's distinctive 16th century Manueline architecture. Several buildings which had suffered little damage due to the earthquake were destroyed by the fire. The brand new Opera House, opened only six months before (under the ill-fated name Phoenix Opera), was burned to the ground. The Royal Palace, which stood just beside the Tagus river in the modern square of Terreiro do Paço, 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 precious royal archives disappeared together with detailed historical records of explorations by Vasco da Gama and other early navigators. The earthquake also destroyed major churches in Lisbon, namely the Cathedral of Santa Maria, the Basilicas of São Paulo, Santa Catarina, São Vicente de Fora, and the Misericordia Church. The Royal Hospital of All-Saints (the biggest public hospital at the time) was consumed by fire and hundreds of patients burned to death. The tomb of national hero Nuno Alvares 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.
Many animals sensed danger and fled to higher ground before the water arrived. The Lisbon quake is the first documented case of such a phenomenon in Europe.
Due to a stroke of luck, the royal family escaped unharmed from the catastrophe. King Joseph I of Portugal 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 Maria I of Portugal began building the royal Palace of Ajuda, which still stands on the site of the old tented camp.
Like the King, the Prime Minister Sebastião de Melo (the Marquis of Pombal) survived the earthquake. Now? Bury the dead and feed the living, he is reported to have said, and with the pragmatism that characterized his coming rule, the Prime Minister immediately began organizing the recovery and reconstruction. He sent firefighters into the city to extinguish the flames, and ordered teams to remove the thousands of corpses. Time was short to dispose of the corpses before disease spread. Contrary to custom and against the wishes of representatives 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, and, in particular, as a deterrant against looting, gallows were constructed as high points around the city and at least 34 were executed. The Portuguese Army was mobilised to surround the city to prevent the able-bodied from fleeing, so that they could be pressed into clearing the ruins.
Not long after the initial crisis, the prime minister and the King quickly hired architects and engineers, and less than a year later, Lisbon was already free from debris and undergoing reconstruction. The King was keen to have a new, perfectly ordained city. Big squares and rectilinear, large avenues were the mottos of the new Lisbon. At the time, somebody asked the Marquis of Pombal the need of such wide streets. The Marquis answered: one day they will be small. Indeed, the chaotic traffic of Lisbon reflects the wisdom of the reply.
Pombaline buildings are among the first seismically-protected constructions in the world. Small wooden models were built for testing, and earthquakes were simulated by marching troops around them. Lisbon's "new" downtown, known today as the Pombaline Downtown (Baixa Pombalina), is one of the city's famed attractions. Sections of other Portuguese cities, like the Vila Real de Santo António in Algarve, were also rebuilt along Pombaline principles.
The earthquake shook much more than cities and buildings. Lisbon was the capital of a devout Catholic country, with a history of investments in the church and evangelisation in the colonies. Moreover, the catastrophe struck on a Catholic holiday and destroyed almost every important church. For 18th century theology and philosophy, this manifestation of the anger of God was difficult to explain.
The earthquake strongly influenced many thinkers of the European Enlightenment. Many contemporary philosophers mentioned or alluded to the earthquake in their writings, notably Voltaire in Candide and in his Poème sur le désastre de Lisbonne (Poem on the Lisbon disaster). The arbitrariness of survival motivated Voltaire's Candide and its satire of the idea that this was "the best of all possible worlds"; as Theodor Adorno wrote, "[t]he earthquake of Lisbon sufficed to cure Voltaire of the theodicy of Leibniz" (Negative Dialectics 361). In the later twentieth century, following Adorno, the 1755 earthquake has sometimes been analogized to the Holocaust as a catastrophe so tremendous as to have a transformative impact on European culture and philosophy.
The concept of the sublime, though it existed before 1755, was developed in philosophy and elevated to greater importance by Immanuel Kant, in part as a result of his attempts to comprehend the enormity of the Lisbon quake and tsunami. Kant published three separate texts on the Lisbon earthquake. (Through the broad later influence of theories of the sublime, the Lisbon earthquake was one factor in a sea change in European aesthetic thought, with an effect which would not be fully appreciated until the late 19th century.) The young Kant, fascinated with the earthquake, collected all the information available to him in news pamphlets, and used it to formulate a theory of the causes of quakes. Kant's theory, which involved the shifting of huge subterranean caverns filled with hot gases, was (though ultimately shown to be false) one of the first systematic modern attempts to explain earthquakes by positing natural, rather than supernatural, causes. According to Walter Benjamin, Kant's slim early book on the earthquake "probably represents the beginnings of scientific geography in Germany. And certainly the beginnings of seismology."
Werner Hamacher has claimed that the earthquake's consequences extended into the vocabulary of philosophy, making the common metaphor of firm "grounding" for philosophers' arguments shaky and uncertain: "Under the impression exerted by the Lisbon earthquake, which touched the European mind in one [of] its more sensitive epochs, the metaphorics of ground and tremor completely lost their apparent innocence; they were no longer merely figures of speech" (263). Hamacher claims that the foundational certainty of Descartes' philosophy began to shake following the Lisbon earthquake.
In Portuguese internal politics, the earthquake was devastating. The Prime Minister was the favorite of the King, but the aristocracy despised him as an upstart son of a country squire. (Although the Prime Minister Sebastião de Melo is known today as Marquis of Pombal, the title was only granted in 1770). The Prime Minister in turn disliked the old nobles, whom he considered corrupt and incable of practical action. Before November 1, 1755 there was a constant struggle for power and royal favour, but afterwards, the competent response of the Marquis of Pombal effectively severed the power of the old aristocratic factions. Silent opposition and resentment of King Joseph I began to rise. This would culminate in an attempted assassination of the King, and the elimination of the powerful Duke of Aveiro and the Távora family.
The Prime Minister's response was not limited to the practicalities of reconstruction. The Marquis ordered a query sent to all parishes of the country regarding the earthquake and its effects. Questions included:
The answers to these and other questions are still archived in the Tower of Tombo, the national historical archive. Studying and cross-referencing the priests' accounts, modern scientists were able to reconstruct the event from a scientific perspective. Without the query designed by the Marquis of Pombal, this would have been impossible. Because the Marquis was the first to attempt an objective scientific description of the broad causes and consequences of an earthquake, he is regarded as a forerunner of modern seismological scientists.
The geological causes of this earthquake and the seismic activity in the region continue to be discussed and debated by contemporary scientists. Since Lisbon is located in a centre of a tectonic plate, there are no obvious reasons for the event, since almost all tectonic events occur at plate borders. Some geologists have suggested that the earthquake may indicate the early development of an Atlantic subduction zone, and the beginning of the closure of the Atlantic ocean.