Lisbon Earthquake of 1761
- When
- 1761
- Where
- SWIM, off the southwest coast of Portugal; Western Europe (felt extent); Lisbon, Portugal
- Episodes
- 3
On 31 March 1761 at 12:05 local time, a powerful earthquake struck off the coast of Portugal, with its epicenter in the SWIM area off the southwest coast. Estimated around 8.5 on the tsunami magnitude scale, it was the strongest in the region since 1755 and was felt across much of western Europe. In Lisbon it caused no serious destruction but damaged leftover wreckage from the 1755 earthquake.
Episodes
- Offshore earthquake strikes Portugal
A strong earthquake struck off the Portuguese coast on 31 March 1761 at 12:05 local time, with its epicenter in the SWIM off the southwest coast.
- Magnitude and felt extent across western Europe
Estimated around 8.5 on the tsunami magnitude scale, the earthquake was the strongest in the region since 1755 and was felt across many parts of western Europe.
- Lisbon experiences lower intensity but 1755 wreckage destroyed
In Lisbon the shaking was felt with lower intensity than in 1755 and caused no serious destruction, though many leftover building wrecks from the 1755 earthquake were destroyed.
Background and detail
Background. The earthquake occurred on 31 March 1761 at 12:05 local time, striking off the coast of Portugal. Its epicenter cannot be fixed precisely, but the general area lies in the SWIM, off the southwest coast of Portugal. The event came less than six years after the devastating 1755 Lisbon earthquake, and seismological study links both that event and the 1969 Lisbon earthquake to slip on faults in the SWIM.
Magnitude and Reach. The earthquake was estimated at around 8.5 on the tsunami magnitude scale, making it the strongest in the region since 1755. Its effects were felt across many parts of western Europe, reflecting the scale of the offshore rupture.
Effects in Lisbon. In Lisbon itself, the shaking was felt with a lower seismic intensity than the 1755 earthquake, and there was no serious destruction. However, many of the leftover building wrecks from the 1755 event were destroyed by the 1761 tremors.
Sources
- 1761 Lisbon earthquake Wikipedia, revision of 2026-09-26
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