Atlantic Ocean Tsunamis
Maps of Atlantic Tsunami Travel Times
Travel Time Maps Composed by NOAA using Tsunami Travel Time Software.
|NOAA Tsunami Reports Map|
Atlantic Ocean Tsunamis: Rare but Possible
A tsunami in the Atlantic Ocean is a rare event. Part of the reason for this low incidence of tsunamis is the lack of subduction zones - the most common source of tsunami-causing earthquakes.
Although the incidence of Atlantic tsunamis is low, the threat should be taken seriously because millions of people live in low-elevation locations around the rim of the Atlantic basin. The travel time maps below show that once a tsunami is generated, the response time for mass evacuation can be uncomfortably short.
The only subduction zones in the Atlantic basin are along the eastern edge of the Caribbean Plate and the eastern edge of the Scotia Plate in the South Atlantic. These subduction zones are small and are not exceptionally active, which accounts for the low incidence of earthquake-generated tsunamis.
Three tsunami-generating earthquakes on the rim of the Atlantic Ocean Basin are described below. Each is accompanied by a calculated travel time map of the Atlantic basin.
Magnitude 7.3, Puerto Rico, 1918
A magnitude 7.3 earthquake in the Mona Passage off the northwest coast of Puerto Rico produced a tsunami on October 11, 1918. This earthquake was probably produced by movement along the boundary between the North American Plate and the Caribbean Plate.
The earthquake generated a tsunami with a local runup height of 6 meters that caused extensive damage and killed over 100 people. A calculated travel time map for a tsunami generated at this source in the Atlantic Ocean, Caribbean Sea, and Gulf of Mexico is shown on this page.
Lisbon, Portugal - November 1, 1755
The most widely known Atlantic Ocean tsunami struck Lisbon, Portugal on November 1, 1755. It was caused by a magnitude 8.6 earthquake beneath the floor of the Atlantic about 100 miles offshore.
This earthquake and associated tsunami destroyed most of the city of Lisbon. Waves up to 12 meters high hit the coastlines of Spain and Portugal just minutes after the earthquake.
About eight hours later, waves with seven-meter runup heights arrived in the Caribbean and caused significant damage. The earthquake and tsunami killed between 60,000 and 100,000 people. A travel time map for this tsunami is shown on this page.
Submarine landslides have caused tsunamis in the Atlantic Ocean.
Grand Banks - November 18, 1929
On November 18, 1929, an earthquake on the southern edge of the Grand Banks, south of Newfoundland, triggered a large submarine landslide that generated a tsunami.
That tsunami was recorded all along the eastern coast of the United States and in the Caribbean Sea. At least 28 people were killed in Newfoundland. A travel time map for this tsunami is shown on this page.
|The Canary Island of La Palma|
Potential Canary Islands Tsunami
Some researchers believe that a large landslide in the Canary Islands could generate a tsunami with basin-wide impact. Faults on the southwest side of La Palma Island associated with Cumbre Vieja volcano could be the detachment surface of a mega-landslide (see satellite image below) .
The idea that this type of landslide in the Canary Islands could produce a large wave with local impact is not disputed. There are numerous large landslides off the coast of the islands.
However, a large number of researchers believe that a landslide-triggered tsunami with basin-wide impact is an "extreme scenario based upon a highly unlikely combination of events that is without precedent" . In 2021, during the eruption of Cumbre Vieja volcano on the island of La Palma, Canary Islands, scientists at the United States Geological Survey said that the "mega-tsunami" hypothesis for the Canary Islands "doesn't carry water".
Based upon a study of landslide debris on the sea floor surrounding the Canary Islands, USGS researchers think that the volume of a potential slide is probably too low to produce a tsunami with basin-wide impact. They also believe that no sediment deposits around the rim of the Atlantic Ocean Basin have ever been found with links to large landslide deposits in the Canary Islands. 
|Map of the Oceans|
|How did the Hawaiian Islands Form?|
|Gifts That Rock|
|Arctic Ocean Seafloor Map|
|Deepest Part of the Ocean|
|What Causes a Tsunami?|
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