A tsunami is a series of ocean waves generated by the rapid, large-scale displacement of a body of water, typically caused by an underwater disturbance like a major earthquake, volcanic eruption, or massive submarine landslide. While the Pacific Ocean is commonly associated with these events, the Atlantic basin presents unique geological scenarios that could generate a tsunami. The possibility of a destructive wave reaching the New York coast is a scientifically recognized, though low-probability, risk. Despite the low probability, the potential consequences in a major metropolitan area necessitate a clear understanding of the science behind this threat to the densely populated Eastern Seaboard.
The Scientific Possibility and Potential Sources
The threat of a tsunami to New York involves two primary mechanisms: a far-field, trans-oceanic event and a near-field, local event. The far-field threat involves massive geological events thousands of miles away, such as a colossal flank collapse of an oceanic volcano. This scenario often focuses on the Cumbre Vieja volcano on La Palma in the Canary Islands, over 3,000 miles from the U.S. East Coast.
Models hypothesize that a catastrophic failure of the volcano’s western flank could drop a massive volume of rock into the Atlantic Ocean, generating a trans-oceanic wave. Earlier simulations suggested potential wave heights of 65 to 80 feet reaching the East Coast, though later research has significantly moderated these estimates. While the collapse is an extremely low-probability event, the scale of the potential displacement means this long-distance threat remains part of hazard planning scenarios.
The more immediate, though still rare, threat comes from a near-field event generated closer to the continental shelf. A major local source involves submarine landslides along the continental slope, such as the area around the Hudson Canyon. Seismic activity or the gradual decomposition of gas hydrates can destabilize the massive sediment deposits accumulated over millennia.
A rapid slump of this material can displace enough water to generate a fast-moving, localized tsunami that would provide very little warning time. Researchers have identified systems of cracks along the outer continental shelf off the Mid-Atlantic coast, suggesting areas of potential instability. The impact of a local landslide-generated tsunami depends highly on the slide’s volume and speed, but it could produce waves comparable to a major hurricane storm surge.
Historical Precedent in the Atlantic Basin
The Atlantic Ocean has a documented history of destructive tsunamis, illustrating that the U.S. East Coast is not immune. The most significant historical example is the 1929 Grand Banks earthquake (magnitude 7.2) off the coast of Newfoundland. The tremor did not directly cause the tsunami but triggered a massive submarine landslide that displaced approximately 200 cubic kilometers of sediment.
The resulting tsunami struck Newfoundland’s Burin Peninsula with waves reaching heights up to 43 feet, claiming 28 lives. The wave was recorded on tide gauges as far south as Charleston, South Carolina, demonstrating trans-basin wave propagation. This event confirms that seismically-induced submarine landslides in the North Atlantic can generate tsunamigenic waves that travel great distances.
Geological evidence also points to ancient landslide events along the U.S. margin. Studies of sediment cores in New York and New Jersey have uncovered deposits of gravel and marine fossils suggesting a wave struck the area approximately 2,300 years ago. Scientists theorize this material was deposited by a high-velocity wave, potentially up to 12 feet high, though the exact source remains under research.
NYC Vulnerability and Specific Impact Zones
New York City’s unique geography and dense coastal development amplify the consequences of even a moderate tsunami event. The city’s low elevation and extensive waterfront infrastructure mean a relatively small wave height could lead to widespread inundation. The New York Bight and the Hudson River mouth could act as a funnel, concentrating the wave’s energy and driving water further inland.
Specific areas are considered at high risk due to their proximity to the open ocean and low-lying topography. The Rockaways in Queens and the eastern and southern shores of Staten Island are directly exposed to the Atlantic and would experience the full force of a wave first. Southern Manhattan, particularly the low-lying areas of Lower Manhattan near Wall Street and the Financial District, is also highly vulnerable to flooding.
Inundation mapping shows that a significant wave would penetrate deeply into coastal neighborhoods, posing a severe threat to infrastructure and life. The underground subway system, particularly in lower Manhattan, presents a specific hazard, as rapid flooding could trap thousands of people. The physical risk is concentrated in areas already within the established hurricane and coastal storm surge evacuation zones.
Warning Systems and Preparedness
The framework for detecting and alerting the public about a potential tsunami threat involves federal and local coordination. The National Tsunami Warning Center (NTWC), operated by NOAA, monitors global and regional seismic activity and ocean conditions for the continental United States. The NTWC issues various levels of alerts, including advisories, watches, and warnings, based on the magnitude and location of the source event and predicted wave heights.
Locally, the NYC Emergency Management (NYCEM) coordinates the city’s response, leveraging communication systems such as Notify NYC and Wireless Emergency Alerts to disseminate information quickly. The challenge in a near-field scenario is the extremely short time between detection and impact, demanding a swift response.
Preparedness efforts largely rely on existing infrastructure designed for coastal flooding and hurricane storm surges. The city’s established hurricane evacuation zones and routes would be utilized in a tsunami scenario. Residents in these zones should be familiar with the routes and seek high ground or vertical evacuation in strong, multi-story buildings upon receiving an official warning.