November 1, 1755. Lisbon, like the entire Catholic world, marks All Saints’ Day, with full churches and thousands of candles burning in honor of saints and martyrs, known and unknown. In the early hours of the morning, the relative calm of the capital was about to be shaken by one of the most destructive earthquakes in recorded history.
Experts diverge for about ten minutes. It was between 9:30 and 9:40 am that the city shook almost uncontrollably, with a vast number of buildings collapsing like house of cards.
Even today, the epicenter of this earthquake in Lisbon is the subject of discussion among the many academics who study the phenomenon. The only thing they agree on is that this epicenter was at sea and that its magnitude would have been 9 at Richter scalethat is, practically the top of the table.
See in this video a possible reconstitution of what happened, in a production of the Smithsonian Channel.
Some contemporary reports state that the seismic shocks were felt over an interminable 9 minutes, opening huge fissures all over the city.
The so-called Lisbon earthquake also hit, and quite severely, the entire Algarve region, having also caused considerable damage in Morocco. But it was in the densely populated Portuguese capital that it caused the most victims.
Of the approximately 300,000 inhabitants that Lisbon had at the time, it is estimated that approximately 90,000 people died as a result of the earthquake and the brutal seaquake that completely swept the lower areas.
lisbon earthquake: the fatal tidal wave
The earthquake caused several fires (powered by the countless candles burning as a result of religious devotion) that consumed medieval Lisbon for days on end.
Another consequence of the earthquake was the formation of a seaquake, or tsunami, with waves that reached 15 to 20 meters in height and entered the city, leaving behind a trail of destruction and death.
The few reports that have survived to this day reveal that due to the various landslides that occurred, as a direct cause of the Lisbon earthquake, the survivors sought shelter near the port area, which was more open and, they thought, safer.
However, it was a death trap. The waters of the sea receded, revealing a bottom littered with the wreckage of ships and lost cargo, only to return with demonic force.
They took everything ahead, submerging the entire port and a substantial part of the city center.
In a matter of minutes, what was then medieval Lisbon disappeared forever. Buildings such as the Teatro da Ópera, the Palace of the Duke of Cadaval, the Royal Palace or the Torre do Tombo Archive (whose documents were saved) collapsed with a bang, with an estimated 10,000 buildings destroyed across the city .
1755 earthquake: the day after
The Portuguese royal family, led by D. José I, was not in the city at the time of the great earthquake, which is due to the simple chance that the princesses wanted to spend the holiday in Santa Maria de Belém, on the outskirts of the capital.
But the impact that the Lisbon earthquake left on the king was perennial. D. José I gained a phobia of closed spaces, living the rest of his life in a luxurious complex of tents in Alto da Ajuda.
A central figure in the entire effort to rebuild the city is Sebastião José de Carvalho e Melo, later the Marquis of Pombal, who is attributed the order “bury the dead, take care of the living”.
It was he who began, almost immediately, plans for the reconstruction of Lisbon, starting with safeguarding security within the urban perimeter itself.
Robberies and looting were judged with a very harsh hand (almost with summary executions), engineers and architects were hired, workers were brought in from other regions, and hands were put to work to build what we know today as the Baixa pombaline.
Lisbon was one of the first cities in the world to have anti-seismic construction buildings. At the time, the wooden models were tested with soldiers marching around them to simulate the impact of an earthquake.
The narrow medieval alleys gave way to wide avenues, so wide in height that many people questioned what roads of those dimensions were for. To these doubts, the Marquês de Pombal replied that “one day they will still find these narrow avenues”. And he was right.
The Lisbon earthquake would thus be the defining moment for a sudden change in the capital, which left its medieval matrix under rubble, assuming itself as a modern city, built through prior planning.
Lisbon earthquake can happen again?
It is a recurring discussion. 268 years ago the earthquake devastated Lisbon. Could it happen again? The answer is yes, of course you can. In fact, there are those who maintain that it is not a question of “if”, but of “when” it will happen. And there are warnings. In 1969 the capital already felt a strong shock, although nothing that compares to that of 1755.
Therefore, being relatively close to an area of great seismic activity, something like this could in fact happen again. It is not known from now a week, a year or centuries. The big question is whether the city is prepared.
Experts don’t think so. In addition to a generalized lack of supervision, there is the fact that some recent constructions practically ignore the necessary anti-seismic procedures for a city like Lisbon.
The only buildings that have some defenses, and even then tampered with, are those built right after the Lisbon earthquake of 1755. It becomes necessary to tighten legislation, and even more so in inspection, so that when something similar happens, losses are minimized .
Predicting an earthquake accurately is still a virtually impossible task.