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Country profile · USGS ComCat

Earthquakes in Portugal

Portugal ranks 49th of 215 countries by catalogued seismic activity - a moderately seismically active country. Below: the full M6+ event history, magnitude and depth profile, and yearly trend, straight from USGS data.

414
M4+ events (since 2005)
11
Major M6+ (since 1900)
M7.8
Strongest
~20
M4+ per year

The verdict

Portugal has logged 414 M4+ earthquakes since 2005 and 11 major M6+ events since 1900, the strongest reaching magnitude 7.8.

#49
of 215 countries by M4+ activity
414
catalogued M4+ events (2005–present)
M7.8
strongest earthquake on record
11
major M6+ events since 1900

Average catalogued magnitude is 4.5 - most events are moderate M4–5 tremors that are felt but rarely cause damage.

Major (M6+) earthquakes in Portugal by year

Count of significant (magnitude 6.0+) events catalogued each year

Value

What this shows Portugal's most active year for major earthquakes was 1969 (3 M6+ events). Major-quake counts are irregular, they track the episodic release of tectonic stress, not a smooth trend.

Source USGS Comprehensive Earthquake Catalog (ComCat) As of 2025

Magnitude distribution of major events

Breakdown of the 11 significant (M6+) earthquakes on record for Portugal.

M7.0-7.9

1

9.1%

M6.0-6.9

10

90.9%

Depth of major earthquakes

Hypocentral depth of the 11 M6+ events, shallow quakes shake the surface hardest. Average depth: 16 km.

Shallow (<70 km)

11

100.0% of events

Intermediate (70–300 km)

0

0.0% of events

Deep (>300 km)

0

0.0% of events

Strongest earthquakes in Portugal

The 10 most powerful events on record (USGS, since 1900).

Mag Location Depth
7.8 188 km SW of Sagres, Portugal 14.5 km
6.7 29 km NE of Ribeira Seca, Portugal 10.0 km
6.7 99 km SE of Senhora do Rosário, Portugal 10.0 km
6.6 91 km SSE of Olhão, Portugal 28.5 km
6.3 74 km SE of Povoação, Portugal 14.0 km
6.2 12 km N of Horta, Portugal 10.0 km
6.2 169 km WSW of Sagres, Portugal 10.0 km
6.1 82 km SE of Senhora do Rosário, Portugal 8.0 km
6.0 181 km SW of Sagres, Portugal 20.0 km
6.0 272 km W of Sagres, Portugal 45.0 km

Significant earthquake record (11 events)

Every catalogued magnitude-6.0-and-above earthquake in Portugal since 1900, most recent first.

Mag Location Depth
6.1 82 km SE of Senhora do Rosário, Portugal 8.0 km
6.3 74 km SE of Povoação, Portugal 14.0 km
6.0 181 km SW of Sagres, Portugal 20.0 km
6.2 12 km N of Horta, Portugal 10.0 km
6.7 29 km NE of Ribeira Seca, Portugal 10.0 km
6.0 272 km W of Sagres, Portugal 45.0 km
6.2 169 km WSW of Sagres, Portugal 10.0 km
7.8 188 km SW of Sagres, Portugal 14.5 km
6.6 91 km SSE of Olhão, Portugal 28.5 km
6.7 99 km SE of Senhora do Rosário, Portugal 10.0 km
6.0 2 km SW of Alcochete, Portugal 10.0 km

Countries with similar seismic activity

Comparable catalogued earthquake frequency to Portugal.

Svalbard and Jan Mayen

431 M4+ events · strongest M6.8

M6.8

Tanzania

368 M4+ events · strongest M6.0

M6.0

Dominican Republic

488 M4+ events · strongest M5.8

M5.8

Yemen

335 M4+ events · strongest M6.6

M6.6

Somalia

331 M4+ events · strongest M5.8

M5.8

Venezuela

526 M4+ events · strongest M7.5

M7.5

Understand the data

How earthquakes are measured

Magnitude scales, seismographs, and depth.

Reading earthquake data

Interpreting magnitude, depth and frequency.

Earthquake preparedness

Before, during and after a quake.

Frequently asked questions

How many earthquakes have occurred in Portugal? ▼
The USGS catalog records 414 earthquakes of magnitude 4.0 or greater in Portugal since 2005, an average of about 20 per year. Separately, 11 significant (M6+) earthquakes are catalogued back to 1900.
What was the strongest earthquake in Portugal? ▼
The strongest catalogued earthquake in Portugal measured magnitude 7.8. Across the full M4+ catalog the average magnitude is 4.5 - most earthquakes are moderate.
How seismically active is Portugal? ▼
By catalogued M4+ activity, Portugal ranks 49th of 215 countries worldwide - a moderately seismically active country. Its busiest year for major (M6+) events was 1969, with 3.
How deep are earthquakes in Portugal? ▼
Across the 11 major (M6+) events on record, the average depth is 16 km. 100% were shallow (under 70 km), where surface shaking is strongest at a given magnitude.
Where does this data come from? ▼
Every figure is derived from the USGS Comprehensive Earthquake Catalog (ComCat). M4+ counts cover 2005 onward (the period of consistent global completeness); the significant-event series covers M6+ back to 1900. Nothing is modelled or estimated.

About this data

Every figure on this page is computed directly from the USGS Comprehensive Earthquake Catalog (ComCat), the public-domain record maintained by the USGS Earthquake Hazards Program. Two series are combined: a worldwide catalog of magnitude-4.0-and-above events from 2005 onward, the period over which the global seismograph network reliably detects and locates earthquakes everywhere, and a historical series of significant magnitude-6.0-and-above events stretching back to 1900. Magnitudes use the moment-magnitude scale (Mw), the modern standard that supersedes the older Richter scale; because the scale is logarithmic, each whole step represents roughly thirty-two times more energy released. Depth is measured in kilometres from the surface, and shallow earthquakes generally produce stronger shaking than deep ones of the same magnitude. Counts reflect what instruments recorded, not every tremor that occurred, and recent events can be revised as seismologists refine the catalog.

Source: USGS ComCat, verify with USGS → · See our methodology for the full pipeline.

Disclaimer: PlainQuake is an informational reference for informational purposes only, not an emergency or early-warning service, and not professional engineering or safety advice. For official alerts and guidance, consult the USGS and your local emergency authorities. See our full disclaimer.