Has There Ever Been a Tsunami on the Eastern Seaboard?

Tsunamis and Earthquakes

• For the most part, tsunamis are caused by earthquakes, the sudden release of high amounts of energy stored in the Earth̵7;s ground. For a tsunami to form, earthquakes must occur deep below the ocean̵7;s surface. When that happens, typically along a fault line, high amounts of water are displaced at the ocean̵7;s surface above the epicenter of the quake. This displacement results in higher-than-normal surface water height. The resulting wall of water will reach far inland when it comes in contact with land.

1929 Grand Banks Tsunami

• A 7.2-magnitude earthquake led to the Nov. 18, 1929, Grand Banks tsunami. The epicenter of the quake was at 44.5 degrees north latitude and 56.3 degrees west longitude, just off the coast of Newfoundland, Canada. Tsunami-like effects were felt as far away as Portugal and South Carolina. In total, the 1929 Grand Banks tsunami caused $400,000 in damage and killed 29 people.

2013 Meteotsunami

• Until recently, not much was known about meteotsunamis, tsunamis caused by weather events rather than earthquakes. Still, a derecho, a large, long-living, sweeping storm with wind gusts approaching 161 kilometers per hour (100 mph), may have been responsible for a tsunami that hit the Eastern Seaboard in the middle of the day on June, 13, 2013. This tsunami caused waters to rise to 1.8 meters (6 feet) and lasted for a couple of minutes. While many questions remain, the strong downdraft from the storm may have been responsible for displacing the large amounts of water that created the tsunami. This effect also occurs occasionally on the Great Lakes. There, it is called a seiche.

Threat of Future Tsunamis

• Compared to the West Coast, the threat of tsunamis on the East Coast is extremely low. For one, earthquakes with enough power to cause tsunamis are rare in the Atlantic Ocean, and they are much more common in the Pacific Ocean. Tsunamis caused by earthquakes, such as the March 2012 temblor that struck Japan, do not occur that often in the Atlantic Ocean. But they can theoretically still occur. In an even more unlikely scenario, a large meteorite striking the Atlantic Ocean would displace enough water to cause a tsunami on the Eastern Seaboard. Finally, while many questions remain, a series of landslides on the ocean bottom caused by a number of small earthquakes could cause a tsunami.