Tsunamis are gigantic waves created by earthquakes that happen at sea. For a tsunamis to occur, there has to be a major adjustment to a tectonic plate of the Earth on the ocean floor bottom, in the deep zone of the ocean. Presently, there is no such fault line in the Atlantic Ocean to suggest such an incident happening. The plates in the Atlantic region are moving away from each other, causing ocean floor spreading, which tends to be a tensional force. A compressional force would be what is needed to cause a tsunamis. A shearing force could also potentially set the stage for such an occurrence, but no strike-slip faults exist in the Atlantic region.
Tsunamis occur when a major upheaval from the Earth's tectonic plates displaces a large amount of ocean water, creating a huge amount of energy dispersal in the form of an ocean wave. As the wave nears the shore of a continent, the shallow ocean bottom concentrates the wave's energy into a larger, wall of water, as much as six times a normal ocean wave. Tsunamis are well known for their tremendous destructive power.
not very likely because the atlantic plates are moving away from eachother and not building up tension that could be released in the form of an earthquake. There is still the chance that an earthquake will occur but it is slim, the next possibility is that a meteor hits the ocean and sends a shockwave to then cause a tusnami.