A similarly massive quake is less likely in the Atlantic Ocean, Popham says. But that doesn’t mean the risk of a tsunami is zero. Underwater avalanches and volcanoes can also move enough water to generate the powerful waves of a tsunami.
To understand why, it helps to imagine the Earth’s crust fitting together like a jigsaw puzzle, and each of the pieces is called a tectonic plate. When plates sliding past each other get stuck, they can build up stress until they finally rupture — causing an earthquake. The earthquakes especially prone to producing tsunamis are the ones that occur where an oceanic plate scoots underneath a continental plate, called a subduction zone.
Unlike the Pacific Ocean, there aren’t any major subduction zones in the Atlantic except the ones underneath the Caribbean Sea. So there are fewer quakes that could generate dangerous tsunamis that would threaten the East Coast. And in the Gulf Coast, none of the tsunamis in recorded history were more than 3.3 feet (1 meter) tall.