What the record shows for Portugal
The strongest earthquake on record near Portugal is a magnitude 6.0 in 1909, centred 2 km SW of Alcochete, Portugal - 117 years ago. The event is catalogued by USGS. See the event record.
Over the last 20 years, USGS has catalogued 12 earthquakes of magnitude 4 or greater within 333 km of Portugal - about one every 2 years. That rate describes how often the ground moves enough to be recorded, not how often damage occurs; most of these are never felt.
Portugal sits in the the SW Iberian margin system, where the pattern is every 1,000–2,000 years. The last major event was the 1755 Lisbon earthquake in 1755 (M8.5), 271 years ago. Its shaking, fire and tsunami destroyed most of Lisbon.
The NOAA NCEI database records 10 tsunamis within 333 km of Portugal between 1531 and 1926. The most significant was in 1755 near Lisbon, triggered by an M8.5 earthquake, which killed around 50,000 people.
Sources: USGS earthquake catalog, NOAA tsunami database, and the Smithsonian Global Volcanism Program. Figures update as the catalogs are revised.
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Portugal and the Azores lie near the Africa–Eurasia plate boundary in the Atlantic.
The only real protection is a warning the moment the ground moves - which is exactly what the free QuakeMate app gives you, along with tsunami and volcano alerts for Portugal.
Earthquake risk in Portugal - FAQ
Is Portugal at risk of earthquakes?
Yes. On average about 1 quake every 2 years nearby of magnitude 4+ within 333 km, based on the last 20 years of USGS data. The strongest earthquake on record nearby is M6.0 in 1909.
What was the biggest earthquake in Portugal?
The strongest earthquake on record near Portugal is M6.0, in 1909 (2 km SW of Alcochete, Portugal), from USGS. Historically, an even larger event - the the 1755 Lisbon earthquake (M8.5, 1755) - is on record for this region.
Does Portugal get tsunamis?
Yes - 10 tsunamis since 1531 (most recently 1926) within 333 km, from the NOAA database. The deadliest killed around 50,000 people.
How do I get earthquake warnings in Portugal?
Download the free QuakeMate app for iPhone. It watches your location and sends a real-time push the instant a quake strikes nearby, plus tsunami and volcano alerts, with custom magnitude and distance rules. On Android, join the waitlist.