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George Pararas-Carayannis

(Excerpts from archives compiled in preparaation of a Catalog of Tsunamis in the Atlantic Ocean, World Data Center A- Tsunami U.S. Dept. of Commerce Environmental Science Service Administration - Coast and Geodetic Survey, May 1969)

© 1997 George Pararas-Carayannis / all rights reserved


In the morning of November 1, 1755, a large earthquake struck Lisbon - a great city legendary for its wealth, prosperity and sophistication. It was Sunday and the religious holiday of All Saints. Most of Lisbon's population of 250,000 were praying in six magnificent cathedrals, including the great Basilica de Sao Vincente de Fora. Within minutes, this great thriving city-port of Lisbon, capital of Portugal and of the vast Portuguese empire and seat of learning in Europe, was reduced to rubble by the two major shocks of this great earthquake and the waves of the subsequent catastrophic tsunami. A huge fire completed the destruction of the great city.

The Great Palace Square of Lisbon

The Great Lisbon Earthquake of 1 November 1755

Earthquake Epicenter and Magnitude

The main shock of the great earthquake struck Portugal at 9:40 in the morning of November 1, 1775. At that time, there were no instruments to record or measure earthquakes but experts have estimated that the magnitude of the Great Lisbon Earthquake must have been 8.6 or even greater. The observations of the effects and the ground motions suggest a moment magnitude closer to 9.0.

The epicenter reported in the literature is 38.0°N, 9.0°W. in the Atlantic Ocean, about 200 km WSW of Cape St. Vincent. However, this estimate appears to be incorrect. It is believed that the epicenter was further south and west than what has been postulated since the first of the tsunami waves reached Lisbon about 40 minutes after the quake struck.

There were three distinct quake shocks over a ten minute period. The first shock was followed by an even more powerful second shock which sent buildings toppling down. According to reports, the tremors and the ground motions from this shock lasted for three-and-one-half minutes. Gigantic fissures of up to 15 feet wide tore through the center of Lisbon. A third shock was less powerful.



Two major aftershocks occurred on December 11 and December 23, 1755 and caused added agony and despair to survivors. Strong aftershocks continued for many weeks.

Tectoning Setting

It is believed that the great Lisbon earthquake occurred along the Azores- Gilbratar fracture zone (AGFZ). AGFZ marks the boundary of active tectonic interaction between the African and the Eurasian plates. This is an active seismic region where large earthquakes occur with frequency. Some of the larger earthquakes, particularly those occurring closer to the eastern section of AGFZ, are capable of generating tsunamis. The tectonic interaction on the eastern segment of AGFZ involves a thrusting component in NW direction along a NE-trending strike plane. Gravimetry measurements support this conclusion.

Lisbon Destruction by the Earthquake

It was Sunday, a beautiful day and a great religious holiday in Portugal when the great earthquake struck. It was a little after 9:30 in the morning and most of the people of Lisbon were either already in the churches or on their way to them.

According to an eye-witnesses, "a strange, frightful noise underground, which resembled the hollow, distant rumbling of thunder," was first heard. He reported that his own house swung from side to side "with a motion like that of a wagon driven violently over wrought stones."

Soon as the quake started, the churches began to rock and sway. The heavy chandeliers began to swing above the heads of the terrified parishioners. Most of the people run to the streets. The first shock was succeeded by a more violent and longer lasting shock.


The quake's rocking ground motions weakened and cracked Lisbon's buildings which collapsed into the city's narrow streets below, crashing the panicked survivors seeking escape. People ran to the edge of the city and into the fields. Others sought refuge on the banks of the Tagus river, only to perish shortly thereafter by the waves of a huge tsunami.

The destruction caused by the earthquake was beyond description. Lisbon's great cathedrals, Basilica de Santa Maria, Sao Vincente de Fora, Sao Paulo, Santa Catarina, the Misericordia - all full of worshipers - collapsed, killing thousands. Lisbon's whole quay and the marble-built Cais De Pedra along the Tagus disappeared into the river, burying with it hundreds of people who had sought refuge.

Earthquake Effects Widely Felt

The Lisbon earthquake caused considerable damage not only in Portugal but in Spain - particularly in Madrid and Seville. The shock waves were felt throughout Europe and North Africa, over an area of about 1,300,000 square miles.

In Europe, ground motions were felt in Spain, France, Italy, Switzerland, Germany, and as far away as the Duchy of Luxembourg and Sweden. Unusual phenomena were observed at great distances. For example, seiches were observed in Finland. In Italy, an ongoing volcanic eruption of Vesuvius stopped abruptly.

Precursory phenomena also had been widely observed prior to the great earthquake. For example in Spain, there had been reports of falling water levels. Turbid waters and a decrease in water flow in springs and fountains had been reported in both Portugal and Spain.

In North Africa the quake caused heavy loss of life in towns of Algeria and Morocco - more than 400 miles south of Lisbon. The town of Algiers was completely destroyed. Tangiers suffered great loss of lives and extensive damage. The earthquake was particularly destructive in Morocco, where approximately 10,000 people lost their lives. Archival records document that the coastal towns of Rabat, Larache, Asilah, and Agadir (named Santa Cruz while under Portuguese rule) suffered much damage. Even the interior cities of Fez, Meknes and Marrakesh were similarly damaged. In Meknes, numerous casualties occurred. Churches, mosques and many other buildings collapsed.

The Great Lisbon Fire

Whatever the earthquake shocks and the tsunami waves spared from destruction, a great fire - which started soon thereafter - finished.

Within minutes the fire spread and turned Lisbon into a raging inferno. Unable to run, hundreds of patients in the Hospital Real burned to death. Remaining survivors ran to the hills and the fields outside the city.

Fanned by steady northeast winds, the great fire burned out of control through the ruins of the city for more than 3 days. It swept everything in its path and destroyed houses, churches and palaces. Lisbon's magnificent museums, and its magnificent libraries - housing priceless documents and papers dealing with the great history of Portugal's great past - burned to the ground. Archives and other precious documents were completely destroyed. Works of art, tapestries, books, manuscripts, including the invaluable records of the India Company were destroyed. Also burned was the king's palace and its 70,000-volume library. Over two hundred fine, priceless paintings , including paintings by Titan, Reubens, and Coreggio, were burned in the palace of the Marques de Lourcal.

Death Toll and Destruction from Earthquake, Tsunami and Fire

The earthquake destroyed Lisbon and other major cities in Portugal. More than 18,000 buildings, representing about 85% of the total were completely demolished. In the first two minutes of the earthquake, about 30,000 people lost their lives. The total death toll in Lisbon, a city of 230,000, was estimated to be about 90,000. Another 10,000 people were killed in Morocco.

Significance of the Great Lisbon Earthquake

The great Lisbon earthquake of 1755, marked the beginning of the modern era of seismology. Following this earthquake there were systematic efforts to catalog the times and locations of earthquakes and to study their physical effects.

The Great Lisbon Tsunami of November 1, 1755


Shortly after the earthquake struck the great city, a series of huge tsunami waves crashed over the harbor quays, engulfed the lower part of Lisbon on the shore of the Tagus, and submerged much of the lower part of the city - including its newly built, marble quay of Cais De Pedra which disappeared into the river.

The first three of these tsunami waves were the largest and completed the destruction brought about by the two earlier strong quake shocks. 20,000 more of the terrified survivors who had rushed to the open space of the docks and the waterfront quay for safety, lost their lives to these tsunami waves. All boats moored in Lisbon's harbor were destroyed.


Eyewitness Account of the Tsunami

Rev. Charles Davy was a survivor of this great Lisbon disaster. The following is an excerpt from his account describing his observations of the tsunami : (Source of historical depiction: Eva March Tappan, ed., The World's Story: A History of the World in Story, Song and Art, 14 Vols., (Boston: Houghton Mifflin, 1914), Vol. V: Italy, France, Spain, and Portugal, pp. 618-628)


"You may judge of the force of this shock, when I inform you it was so violent that I could scarce keep on my knees; but it was attended with some circumstances still more dreadful than the former. On a sudden I heard a general outcry, "The sea is coming in, we shall be all lost." Upon this, turning my eyes towards the river, which in that place is nearly four miles broad, I could perceive it heaving and swelling in the most unaccountable manner, as no wind was stirring. In an instant there appeared, at some small distance, a large body of water, rising as it were like a mountain. It came on foaming and roaring, and rushed towards the shore with such impetuosity, that we all immediately ran for our lives as fast as possible; many were actually swept away, and the rest above their waist in water at a good distance from the banks.

For my own part I had the narrowest escape, and should certainly have been lost, had I not grasped a large beam that lay on the ground, till the water returned to its channel, which it did almost at the same instant, with equal rapidity. As there now appeared at least as much danger from the sea as the land, and I scarce knew whither to retire for shelter, I took a sudden resolution of returning back, with my clothes all dripping, to the area of St. Paul's. Here I stood some time, and observed the ships tumbling and tossing about as in a violent storm; some had broken their cables, and were carried to the other side of the Tagus; others were whirled around with incredible swiftness; several large boats were turned keel upwards; and all this without any wind, which seemed the more astonishing.

It was at the time of which I am now speaking, that the fine new quay, built entirely of rough marble, at an immense expense, was entirely swallowed up, with all the people on it, who had fled thither for safety, and had reason to think themselves out of danger in such a place: at the same time, a great number of boats and small vessels, anchored near it (all likewise full of people, who had retired thither for the same purpose), were all swallowed up, as in a whirlpool, and nevermore appeared.

This last dreadful incident I did not see with my own eyes, as it passed three or four stones' throws from the spot where I then was; but I had the account as here given from several masters of ships, who were anchored within two or three hundred yards of the quay, and saw the whole catastrophe. One of them in particular informed me that when the second shock came on, he could perceive the whole city waving backwards and forwards, like the sea when the wind first begins to rise; that the agitation of the earth was so great even under the river, that it threw up his large anchor from the mooring, which swam, as he termed it, on the surface of the water: that immediately upon this extraordinary concussion, the river rose at once near twenty feet, and in a moment subsided; at which instant he saw the quay, with the whole concourse of people upon it, sink down, and at the same time every one of the boats and vessels that were near it was drawn into the cavity, which he supposed instantly closed upon them, inasmuch as not the least sign of a wreck was ever seen afterwards.

This account you may give full credit to, for as to the loss of the vessels, it is confirmed by everybody; and with regard to the quay, I went myself a few days after to convince myself of the truth, and could not find even the ruins of a place where I had taken so many agreeable walks, as this was the common rendezvous of the factory in the cool of the evening. I found it all deep water, and in some parts scarcely to be fathomed."

Tsunami Effects in the Tagus River Estuary in Lisbon and along the west and south coasts of Portugal.

For most coastal regions of Portugal, the destructive effects of the resulting tsunami were more disastrous than those of the earthquake. The first three of the tsunami waves were particularly destructive along the west and south coasts of Portugal.

At the mouth of the Tagus river estuary and upstream , there was an initial recession of the water which left exposed large stretches of the river bottom. Shortly afterwards, the first of the tsunami waves arrived. It swamped Bugie Tower and caused extensive damage to the western part of Lisbon, the area between Junqueria and Alcantara. The same wave continued upstream spreading destruction and demolishing the Cais de Pedra at Terreiro do Paco and part of the nearby custom house. The maximum wave height at this location was estimated to be about 6 meters. Boats which were overcrowded with quake survivors seeking refuge, capsized and sank. There were two more large waves. It is estimated that the largest tsunami runup in the Tagus estuary was about 20 meters.

At the coastal town of Cascais, about 30 km west of Lisbon, large stretches of the sea floor were initially exposed, then the arriving tsuinami waves demolished several boats. At Peniche, a coastal town about 80 km north of Lisbon, many people were killed by the tsunami. In Setubal, another coastal town 30 km south of Lisbon, the water reached the first floor of buildings.

The tsunami destruction was particularly severe in the province of Algarve, in southern Portugal, where almost all the coastal towns and villages were severy damaged, except Faro, which was protected by sandy banks. In some coastal regions of Algarve, the maximum tsunami wave runup was 30 meters. According to reports, the waves demolished coastal fortresses and razed houses to the ground. In Lagos, the waves reached the top of the city walls.

Tsunami Generating Area

In 1755, there were no instruments in existence to record the Lisbon earthquake and thus determine its epicenter. The epicenter was reported to have been at 38.0°N, 9.0°W. , about 200 km WSW of Cape St. Vincent. However the tsunami travel time to Lisbon was approximately 40 minutes, which suggests that the epicenter and the tsunami generating area must have been further south and west of the reported location.

Generating Areas of the 1755 and 1969 tsunamis along the Azores-Gibraltar Fracture Zone (AGFZ) superimposed on bathymetry and gravity anomaly map (Source: Pararas-Carayannis, 2001)

Numerical modeling studies of the small tsunami generated by the February 28, 1969 quake in the same general area of the Atlantic (Heinrich, Batista, and Miranda, 1994), have suggested that the epicenter of the Lisbon earthquake was close to that of the 1969 event which produced only a small tsunami. The epicenter of the 1969 quake was centered south of Gorringe bank near the Azores-Gibraltar fracture zone in the Atlantic Ocean (see map). However, the travel time to Lisbon for the first wave of the 1755 tsunami indicates that its generating area was somewhat north of the 1969 event. It took about 40 minutes for the first wave to reach Lisbon in 1755. The travel time to Lisbon from the 1969 quake was closer to 50 minutes. Also, the first wave in 1755 was negative, which indicates that the wave originated from a region of subsidence, while the 1969 wave was positive from an area of upthrust.

In the absence of seismological source parameters for the 1755 Lisbon quake, Dr. Charles Mader used the reported Lisbon tsunami wave characteristics to estimate source dimensions and tsunami travel times (personal communication March 2001, see also reference below). Since the initial tsunami wave was a drop of about 20 meters in Lisbon and the observed period was about 1 hour, he postulated that the tsunami generating area was fairly wide, involving considerable ocean floor subsidence. He estimated that a tsunami source region of about 300 kilometers in radius (282,000 square kilometers), dropping about 30 meters, could generate the type of wave which occurred in Lisbon.

As presented earlier, the epicenter of the the 1755 Lisbon earthquake could not have been at 38 N, 9 W, as postulated because there is no significant tectonic interaction at this location. More likely the quake's epicenter and the tsunami generating area were further south and west. A more probable tsunami generating area - where subsidence is possible - would have been north of the Gorringe Bank along the Azores- Gilbratar fracture zone (AGFZ), rather than south where the 1969 tsunami was generated (and as postulated by Heinrich, Batista, and Miranda (1994)).

AGFZ marks the boundary of active continent to continent convergence between the African and the Eurasian plates. Compression along this boundary appears to result in an echelon overlapping and staggering arrangement of a series of faults, some being thrust or reverse types with the net result being a wide distribution of grabbens and horsts. These oceanic features have resulted from subsidence or upward displacements of crustal blocks. Each of these features is relatively short, but collectively they form the wide linear zone, known as the AGFZ, in which the strike of the individual features is oblique to that of the zone as a whole.

The AGFZ is an active seismic region where large earthquakes can occur with frequency. Some of the larger earthquakes, particularly those occurring closer to the eastern section of AGFZ are capable of generating tsunamis. The tectonic interaction on the eastern segment involves a thrusting component in NW direction. However, because of differences in source parameters and mechanisms of continent to continent compression (and possibly triple junction interaction with the Atlantic oceanic plate), each earthquake in this region, regardless of magnitude, will not have the same efficiency for tsunami generation. This is the reason why the 1969 quake generated a small tsunami, even though it had a rather large magnitude , Ms=7.9, and involved thrust faulting. It is believed that the tsunamigenic efficiency of the 1755 Lisbon earthquake was greater because of large scale subsidence caused by continent to continent convergence and compression. The generating area was in the abyssal plain, north of the Gorringe Bank along the Azores- Gilbratar fracture zone (AGFZ), a region characterized also by negative gravity anomalies.

Tsunami Travel Times and Heights

About 30 minutes after the earthquake struck Lisbon, the sea level near the Bugie Tower at the mouth of the Tagus river, begun to recede. About 10 minutes later the first large wave arrived, so the tsunami travel time from the source region to Lisbon was approximately 40 minutes. It took less than an hour for this first tsunami to reach Morocco and Algiers, and about 7 hours to reach the Caribbean and the U. S. East coast.

Atlantic-Wide Tsunami Effects

Remarkable tsunami waves and effects were recorded and reported everywhere, on both sides of the Atlantic. Waves up to 60 feet in height hit a vast area stretching from Finland to North Africa and across the Atlantic to Martinique and Barbados causing much destruction and loss of life. Lakes as far north as Sweden were affected as well as the river Dal in Norway, 1800 miles (about 2,890 kilometers) away, which overflowed its banks.

Spain: In southwestern Spain, the tsunami caused damage to Cadiz and Huelva, and the waves penetrated the Guadalquivir River, reaching Seville.

Gibraltar: In Gibraltar, the sea rose suddenly by about two meters. In Ceuta the tsunami was strong,

Mediterranean Sea: in the Mediterranean Sea, it decreased rapidly.

Morocco: Caused great damage and casualties to the western coast of Morocco, from Tangier, where the waves reached the walled fortifications of the town, to Agadir, where the waters passed over the walls, killing many.

France Great Britain, Ireland, Belgium and Holland: The tsunami reached, with less intensity, the coast of France, Great Britain, Ireland, Belgium and Holland.

Madeira and the Azores islands: Madeira and in the Azores islandsdamage was extensive and many ships were in danger of being wrecked.

Antilles, Antigua, Martinique, and Barbados: The tsunami crossed the Atlantic Ocean, reaching the Antilles in the afternoon. Reports from Antigua, Martinique, and Barbados note that the sea first rose more than a meter, followed by large waves.

Numerical Modeling Studies of Tsunami Travel Times and Heights

Using the postulated tsunami source parameters {300 kilometers radius (282,000 square kilometers), and about 30 meters of subsidence} Dr. Mader' numerical modeling study provided estimates of the tsunami travel time and the deep water tsunami wave amplitudes along the east coast of USA, in the Caribbean and the Gulf of Mexico.

Travel Time Chart of the Great Lisbon Tsunami (Source: Dr. Charles Mader)

Based on this computer simulation, he estimated that the offshore deep water tsunami amplitudes along the USA coast and the Caribbean must have been about 2 meters high with periods of 1.25 to 1.5 hours. The maximum tsunami runup on the shore would have been about 10 feet (about 3 meters). In the Gulf of Mexico the offshore tsunami deep water amplitudes would have been less than a meter.




The deep water, tsunami height estimates for the U.S. East Coast, the Caribbean and the Gulf of Mexico seem reasonable. Actual tsunami runup on the shore would have been higher depending on the local bathymetry and the coastal configurations.

The Great Lisbon tsunami of 1755 was most probably generated in the abyssal plain north of the Gorringe Bank along the Azores- Gilbratar fracture zone (AGFZ). The bathymetry, gravity anomalies and overall geomorphological features of the easterrn segment of the AGFZ indicate the existence of a large area of subsidence, characterized by a grabben with an approximate orientation of N45E caused by continent to continent collision.

The eastern section of AGFZ is an area of active tectonic interaction, capable of producing large earthquakes with variable tsunamigenic efficiencies. Although the Lisbon earthquake of 1755 was a rare and unusual combination of seismic and tsunami events, a recurrence in the future is a certainty. However, in the absence of adequate historical earthquake data, it is not possible to provide a statistical probability as to when an event similar to the Great Lisbon Earthquake and Tsunami of 1755 may reccur.


Heck, N.H.,1947, List of seismic sea waves, Bull. Seismol. Soc. Am., v. 37, no. 4, p. 269-284.

Mader, Charles, 2001, Modeling the 1755 Lisbon Tsunami, Mader Consulting Co., Honolulu, Hawaii, u.S.A.

Milne, J. 1912, Catalog of destructive earthquakes, Brit. Assn. Adv. Sci. Rept. 81st Mtg., 1911, p. 649-740.

Myles, Douglas, 1985, "The Great Waves" - Tsunami, Foreword by G. Pararas-Carayannis, 206pp, McGraw Hill, 1885.

Myles, Douglas, 1986, "The Great Waves" - Tsunami, Foreword by G. Pararas-Carayannis, 206pp, Robert Hale Ltd, London, 1986.

Pararas-Carayannis, George, 2001, The Potential for Tsunami Generation along the Azores-Gibraltar Fracture Zone, (unpublished paper).

Pararas-Carayannis, George, 2001,Tsunamigenic Efficiency, (Unpublished Paper).

Svyatlowski, A.E., 1957. Tsunamis--destructive waves originating with underwater earthquakes in seas and oceans [Russian], Izdatel'stvo Akad. Nauk SSSR, p. 1-69, Eng. transl. by V. Stevenson, Hawaii Inst. Geophys., Transl. Ser. 8, 1961.

Kozak, Jan T., and James D. Charles, Paper abridged and edited from drafts of a longer work in progress by V. S. Moreira, C. Nunes and J. Kozak on the Lisbon Earthquake of 1755. Institue of Rock Mechanics, Czech Academy of Science , National Information Service for Earthquake Engineering (NISEE) of the University of California, Berkeley,

Tappan March Eva, ed., 1914. The World's Story: A History of the World in Story, Song and Art, 14
Vols., (Boston: Houghton Mifflin, 1914), Vol. V: Italy, France, Spain, and Portugal, Source: Modern History Sourcebook: Historical Depictions of the 1755 Lisbon Earthquake Rev. Charles Davy: The Earthquake at Lisbon, 1755, pp. 618-628.

Some of the images presented here have been modified from the Kozak Collection of Images of Historical Earthquakes, National Information Service for Earthquake Engineering (NISEE) of the University of California, Berkeley, from the Lisbon Museum and from unpublished work of Dr. Charles Mader (permission granted).


©1982 - 2013 Dr. George Pararas-Carayannis - All rights reserved

Last update: MARCH 21, 2013