The 1761 Lisbon earthquake, estimated at magnitude 8.5, was the largest seismic event in the region since the devastating 1755 Lisbon earthquake.
Key Facts
- Date
- 31 March 1761
- Surface-wave magnitude
- 8.5 Mw
- Geographic extent
- Felt from Scotland and Amsterdam to Morocco and Canary Islands
- Previous comparable event
- Great Lisbon earthquake of 1755
- Government response
- Portuguese government censored information to prevent panic
By the Numbers
Location
Cause → Event → Consequence
The north Atlantic Ocean and the region south of the Iberian Peninsula are seismically active zones. Coming only six years after the catastrophic 1755 Lisbon earthquake, the area remained geologically unstable, and tectonic stress along the same fault systems produced another major rupture.
Just after noon on 31 March 1761, a violent earthquake estimated at surface-wave magnitude 8.5 struck in the north Atlantic Ocean south of the Iberian Peninsula. The shock was felt across much of Western Europe and Morocco, and generated a subsequent tsunami. It was the largest seismic event in the region since the 1755 earthquake.
Significant damage occurred in older parts of Lisbon, particularly to structures already weakened by the 1755 earthquake. The Portuguese government suppressed much information about the disaster to prevent public panic in the still-recovering city, leaving historical records sparse and the full extent of damage difficult to assess.