On the morning of Monday, February 17, 2025, a 4.7-magnitude earthquake on the Richter scale struck Lisbon and nearby regions, including Setúbal. The tremor was felt by residents in various parts of the city, causing moments of tension and alert. The Portuguese Institute for the Sea and Atmosphere (IPMA) confirmed the earthquake, with its epicenter located about 14 km from Setúbal and 24 km from the Portuguese capital. The European-Mediterranean Seismological Centre (EMSC) initially estimated the magnitude at 4.9 but later revised it to 4.7, aligning with IPMA’s data. So far, there have been no reports of casualties or significant structural damage, but authorities continue to monitor the situation and assess the possibility of aftershocks.
The population of Lisbon and surrounding areas reported feeling the tremor moderately. Many residents left their buildings in search of safety.
IPMA stated that it is still monitoring the situation and warns of possible aftershocks in the coming days, reinforcing the importance of following safety guidelines.
ℹ️ #Sismo | Portugal Continental
— Autoridade Nacional de Emergência e Proteção Civil (@ProteccaoCivil) February 17, 2025
Hoje, dia 17 de fevereiro, pelas 13:24 (hora local), foi registado um sismo de magnitude 4.7 (Richter) e cujo epicentro se localizou a oeste do Seixal.
Não há registo de danos pessoais ou materiais até ao momento. pic.twitter.com/0oVSCmS08n
History of Earthquakes in Lisbon and Surrounding Areas
Portugal, especially the Lisbon region, has a significant history of earthquakes. The most catastrophic seismic event occurred in 1755, when an earthquake estimated between 8.5 and 9.0 magnitude destroyed much of the city. The tremor was followed by a tsunami and fires that worsened the tragedy, resulting in the deaths of approximately 60,000 people.
Another significant tremor occurred in 1969, measuring 7.9 on the Richter scale. Although less devastating than the 1755 earthquake, it caused considerable damage and reinforced the need for continuous monitoring. In August 2024, a 5.4-magnitude earthquake was felt in the capital, reigniting concerns about the region’s seismic vulnerability.
Lisbon and other parts of Portugal are located in a tectonically active zone, where the Eurasian and African plates meet. This factor contributes to frequent seismic activity, making a robust monitoring and prevention system essential.
How the Richter Scale Works and Its Impacts
The Richter scale was developed in 1935 by seismologists Charles Richter and Beno Gutenberg to measure the magnitude of earthquakes. It is a logarithmic scale, meaning that each increase of one point represents an energy release approximately 31.6 times greater than the previous level.
- Tremors between 2.0 and 3.9: Usually not felt by the population.
- Tremors between 4.0 and 4.9: Can be perceived but rarely cause structural damage.
- Tremors between 5.0 and 5.9: May cause minor damage to weaker buildings.
- Tremors between 6.0 and 6.9: Cause significant damage, especially to less prepared structures.
- Tremors above 7.0: Have great destructive potential, affecting vast areas.
The earthquake recorded in Lisbon, with a magnitude of 4.7, falls into the category of perceptible tremors but with no expectation of major destruction. However, its occurrence reinforces the need to remain vigilant, especially due to the possibility of aftershocks.
IPMA’s Role in Seismic Monitoring
The Portuguese Institute for the Sea and Atmosphere (IPMA) is the agency responsible for monitoring seismic activity in Portugal. The institution operates a network of seismographs distributed throughout the country, recording and analyzing tremors in real-time.
Following this morning’s tremor, IPMA emphasized that although there are no reports of damage, it is essential for citizens to remain alert. The agency recommends that residents follow safety instructions, avoid unstable structures, and prepare for possible aftershocks.
How to Act During an Earthquake
In the event of an earthquake, it is essential to follow safety measures to minimize risks. Some of the main recommendations include:
- During the tremor
- Seek shelter under tables or sturdy furniture.
- Stay away from windows, mirrors, and objects that may fall.
- If outdoors, move away from buildings, trees, and power poles.
- After the tremor
- Check for structural damage to homes and buildings.
- Avoid using elevators.
- Follow official information and instructions from authorities.
- In case of evacuation
- Have an emergency kit prepared with essential items, such as water, non-perishable food, and medication.
- Set a safe meeting point with family members.
- Stay calm and follow recommended evacuation routes.
The Importance of Earthquake Preparedness
Portugal has made significant investments in infrastructure to minimize the impact of earthquakes. Reinforcing historic buildings and implementing stricter construction regulations are some of the strategies adopted to reduce risks.
Besides governmental measures, public awareness is a key factor. Regular training and drills can help ensure that citizens know how to act in an emergency.
Possibility of Aftershocks and Continuous Monitoring
After an earthquake, the possibility of aftershocks is high, especially within the first 24 hours. These aftershocks can vary in intensity, with some being noticeable and others not. IPMA continues to monitor the situation and will keep the public informed about new developments.
Seismic events like the one that occurred this morning highlight the importance of continuous monitoring and preparedness for possible future tremors. Although the 4.7-magnitude earthquake did not cause damage, its occurrence serves as a reminder that Lisbon must continue improving its strategies for mitigating natural disasters.
