The Great Earthquake of Lisbon

Updated: Mar 18

If there was an event that changed the history of Lisbon, it was the Great Earthquake on the 1st of November 1755. It destroyed most of the city and it changed the life of Lisbon forever.


It was a calm sunny morning in Lisbon and people were ready for the celebrations of All Saints day but few hundred kilometers away, southwest of the Portuguese Coast, in a junction area of the Eurasian and African plates, one plate slipped underneath the other, creating a shock wave that spread along the surface of both. At the same time, the sudden lowering of the sea floor created a wave that quickly broke in several directions. It was nine forty in the morning when suddenly, the first of the three Earthquakes hit the city.


The first one was small and lasted for about a minute but after an interval of 30 seconds, the shock was so violent that buildings began to fall. This time, the tremor lasted for about two minutes, after which the land rested for less than a minute and started to shake again, knocking over the buildings that still resisted. According to accounts, this last tremor lasted for three minutes.


The center of Lisbon was wrapped in a great cloud of dust that blocked the sun and seemed to amplify even more the moans and cries of those who were buried or wept the loss of their loved ones.


Some of the survivors went to Terreiro do Paço, the biggest square of the city, trying to find a safe place to hide but unaware of the giant waves that were on their way towards Lisbon and had already destroyed many cities in the Algarve. According to a witness, “the waves tore anchors, broke mooring and entered the streets and squares of the neighborhood. Most of those who had gone in search of shelter on the banks of the river were carried out by the waves, without anyone being able to help them”.


Recent calculations indicate that the first wave of the tsunami generated by the earthquake at the bottom of the Atlantic Ocean (between 8.5 to 9.5 on the Richter scale), moved at a speed of 100 to 200 meters per second. The number of waves caused by this tsunami is now estimated at 16, but the reports in Lisbon unanimously refer to three large waves that probably reached as far as the place where Rossio is located nowadays.


According to the same witness, we can understand the dimension of the tragedy that seemed to have no end: “the earth, the air and the water had united against miserable Lisbon and its scared citizens. Only fire was missing to complete our ruin. We were soon to experience this terrible scourge”


It is said that there were fires in at least 100 different places at the same time and they continue to burn for six consecutive days without any interruption or any attempt to control them. It consumed everything the earthquake had spared. The terror was permanent, the aftershocks of the earthquake continuing into the afternoon and night of November 1st.


Almost everyone fled the city by night due to the risk of explosion of the stored gunpowder in the Castle, which never happened but the zone destroyed by the fire occupied a mile circumference. The exactly number of casualties was never known but it’s believed between 20.000 and 90.000 passed on that day.


A painting showing the ruins of Lisbon's Cathedral by Jacques Philippe Le Bas

The day that marked the before and after of Lisbon’s life came to an end, but it affected the way people came to face natural catastrophes, their relationship with science, divine power and city planning.


The reconstruction of Lisbon


Most of Lisbon was destroyed, including the Royal Palace. The king was traumatized and moved to the outskirts, where he lived in tents for the next couple of years. The reconstruction of Lisbon was in charge of one man, the visionary Prime Minister Sebastião José de Carvalho e Melo, the Marquees of Pombal.


He organized the army to watch over pillage and started to organize the reconstruction. He decided to build a modern city, guided by the French architectural trends of the 18th century. The project was composed of parallel and perpendicular large streets with different categories of importance. The central street was named "Rua Augusta", starting with a magnificent arch at the Commerce Square and ending at Rossio Square.


From an innovative perspective, the architects of the new city implemented measures to diminish damage in the event of another catastrophe and introduced new techniques when it comes to infrastructure, such as the use of the famous “gaiolas pombalinas” (pombaline cages), a structure with anti-seismic characteristics, the use of fire-resistant walls between the buildings, functional use of tiles indoors, construction of elevated sidewalks exclusively for pedestrians and the creation of domestic sewage.


It’s estimated that the earthquake cost between 32 and 48 percent of Portugal’s GDP and more significantly, the earthquake became an opportunity to reform the economy and to modernize Lisbon.