On 1 November 1755, an earthquake with a magnitude of 8.7–9 almost completely destroyed Lisbon. More than 270 years later, its consequences are still visible in the city’s everyday life: in strict rules for building and renovation, in the marked safe zones in case of a tsunami, and in school drills where children learn what to do when the ground starts shaking. Journalist and researcher of Portuguese history Alena Khazinurova explains for Xpat.Land how Lisbon still lives with the memory of the disaster, and how ready it is for the next one.
Also read Xpat.Land’s pieces on the earthquake, featuring eyewitness accounts, and on how prepared the country is for seismic activity today.
Will the buildings collapse?
In the first years after the 1755 disaster, the authorities, led by the Marquis of Pombal, whose name is now one of the best known in Portugal, rebuilt the entire city centre, today’s Baixa district.
All the new buildings were fitted with the “Pombaline cage” (gaiola pombalina), a timber frame inside the walls designed to absorb vibrations during an earthquake. It wasn’t the first earthquake-resistant structure in human history: similar solutions already existed in Japan. But Portuguese engineers were very likely the first in the world to carry out seismic testing, ordering soldiers to march rhythmically around models of the buildings to see how they responded to vibration.
Buildings constructed in Lisbon right after 1755 are still considered relatively safe. The same can’t be said for those from the early 20th century: the city was growing fast, apartment blocks and the first reinforced-concrete structures were going up, but there were no uniform standards yet.
The first serious regulation appeared in 1958 and, with some updates, remained in force until 2019. It divided Portugal into zones of different seismic hazard for the first time, with Lisbon placed in the highest-risk zone. Engineers and designers were required to factor the “horizontal forces” generated during an earthquake into their calculations.
In 2019 Portugal adopted the pan-European building standards (Eurocodes), which include separate seismic safety rules. Since the same year, a separate ordinance has required owners to have a building’s seismic resistance assessed when carrying out major reconstruction or alterations. In particular, if the building’s structural layout changes, another 25% of its floor area must be rebuilt or added. In older buildings in and around Lisbon, getting a permit for major renovation can be difficult, partly because of these requirements.
The safety statistics are not reassuring: as of August 2024, only 12% of buildings in Portugal fully complied with modern seismic standards, and two-thirds of Lisbon’s housing stock was built before any seismic regulations existed. According to scientists’ projections, if an earthquake on the scale of 1755 struck in the coming years, it would kill more than 12,000 people in Greater Lisbon.
You can get a sense of how vulnerable your building is from its construction date (before 1958: not great; 1958–2019: better; from 2019: you’re among the lucky 12%) and by checking your address on the soil seismic vulnerability map.
Will the earthquake happen again?
It’s too early to panic and pack your bags: experts consider a repeat of the 1755 disaster in the foreseeable future extremely unlikely. According to research, events like this happen rarely, once every 1,500 to 4,000 years.
But you shouldn’t relax completely either. Portugal does have moderate seismic activity, if only because two tectonic plates meet nearby: the Eurasian and the African. Minor tremors are felt here fairly often. The most recent noticeable ones were on 26 August 2024 (magnitude around 5) and 17 February 2025 (magnitude 4.8).
There’s a popular myth that this is actually a good thing: supposedly, the energy built up along the plate faults is released gradually rather than in one powerful jolt. Seismologists, however, disagree: small tremors can’t release enough accumulated tectonic stress to prevent major disasters.
But are we ready?
In case a major disaster strikes again, Lisbon does, in theory, have a plan. The city has set up a network of 86 emergency meeting points (Pontos de Encontro de Emergência) with capacity for more than 600,000 people. They are usually on high ground or in parks, away from buildings and hazards such as gas pipelines. You can find the one nearest you on the map. You can also check your area’s flood risk in the event of a tsunami.
The city also has an SMS emergency alert system and a siren system. The latter so far consists of just four loudspeakers in central Lisbon, but by 2029 it is due to grow to ten along the entire Tagus waterfront. The sirens were tested for the first time in March 2026, but it turned out that many residents didn’t hear them, even on the waterfront less than 500 metres from the source. The system is now being improved.
For earthquakes of magnitude 6.1 and above, the city is supposed to activate a special emergency response plan for all rescue services. The trouble is, this plan was adopted in 2009 and hasn’t been revised since. It was recently discovered that the document doesn’t mention social media once, even though they are now a major source of information, and the word “internet” appears just three times in 99 pages.
The Portuguese learn how to behave during an earthquake from school onwards. Every year the country holds a national drill, A Terra Treme (“The Earth Shakes”), for children and adults, and schoolchildren also get special talks on safety measures.
