Tsunami Animation for the Great Lisbon Earthquake of 1755
On the morning of
November 1,
1755, a great earthquake shook
Portugal's capital city of
Lisbon as worshipers filled churches and cathedrals for the
All Saints' Day Mass. In seconds it left the city in ruins and in minutes those ruins were on fire. The earthquake probably killed about 30,
000 people, though some estimates double that figure. Many of the survivors fled to the wharves and keys of Lisbon's port, but they would find no safety there. The first tsunami wave surged up the
Tagus estuary about an hour after the earthquake, reached a maximum runup of
12 meters (40 feet), and killed another
1000 people. At least two more tsunami waves surged into the city, completing the earthquake's destruction.
At Portugal's coastal city of
Lagos the tsunami was even larger, perhaps 30 m (
100 ft). It went on to damage the ports of
Cadiz in
Spain, then
Safi and
Agadir in
Morocco. The tsunami also spread north: it caused minor damage at
Brest in
Brittany, some flooding in
England in the
Scilly Islands and in
Cornwall, and extensively flooded of the low-lying areas of the city of
Cork, Ireland. As it spread out across the
Atlantic, the tsunami first reached
Madeira, where observers recorded a runup of 4 m (13 ft), then the
Canary Islands, the Azores, and eventually the
West Indies, where observers recorded runups of about a 1 m (3 ft) in
Barbados,
Martinique,
Guadeloupe, and Antigua (and questionable reports of large runup in the
Virgin Islands). Though the tsunami must have hit
Colonial America, no one recorded it there, though it was observed in
Newfoundland.
Our model of this tsunami assumes its source was a magnitude 8.5 earthquake on the
Horseshoe Fault off of
Cape Finisterre. Baptista, et al. (
2011) explain how this fault matches the tsunami observations better than the several other proposed sources for the
Great Lisbon Earthquake.
Reference: Baptista,
M.A.,
Miranda,
J.M.,
Omira, R., & Antunes, C. (2011). "Potential inundation of
Lisbon downtown by a 1755-like tsunami."
Natural Hazards and
Earth System Science, 11(12), 3319--3326.