A tsunami is a series of powerful waves caused by the displacement of a large volume of water, typically in the ocean. This displacement is most often triggered by an underwater earthquake, but it can also result from a massive landslide, volcanic eruption, or meteorite impact. These gravity waves can travel across open water at speeds comparable to a jet plane. Understanding the historical context and potential sources of these events is important for coastal communities like Myrtle Beach, even though the risk here is low.
The Historical Record for Myrtle Beach
Myrtle Beach and the wider South Carolina coast have not experienced a destructive, seismically generated tsunami in recorded history comparable to events in the Pacific. The most significant historical wave action noted along the East Coast was the signal from the 1929 Grand Banks earthquake, recorded as far south as South Carolina. This event was caused by a magnitude 7.2 earthquake that triggered a massive submarine landslide off the coast of Newfoundland, Canada.
Another notable event was the 1886 Charleston earthquake, a powerful magnitude 7.3 quake with an onshore epicenter. While the earthquake caused widespread damage, it generated only a small wave noted in the Copper River in South Carolina and along the coast of Florida. The waves recorded during these historical events were generally small and did not cause the widespread inundation typical of a major tsunami.
Sources of Atlantic Tsunami Activity
The United States East Coast sits on a passive continental margin, meaning there are no active plate boundaries or major subduction zones nearby. This geological setting is the primary reason the East Coast is significantly less prone to tsunamis than the Pacific coasts, where tectonic plates actively converge.
The most significant theoretical threat for a damaging tsunami in the Atlantic basin comes from massive, underwater slope failures or submarine landslides. These landslides, which can be triggered by a smaller seismic event or occur spontaneously, can displace huge amounts of water, creating a tsunamigenic wave. Another distant source is large seismic activity across the Atlantic, such as the Azores-Gibraltar fault zone, which produced the destructive 1755 Lisbon earthquake and tsunami. Scientists also study the potential for a catastrophic flank collapse of the Cumbre Vieja volcano in the Canary Islands.
Local Warning and Safety Protocols
Despite the low probability of a major event, Myrtle Beach has been designated a “TsunamiReady” community by the National Weather Service, leveraging its existing hurricane preparedness infrastructure. The National Tsunami Warning Center (NTWC) continuously monitors seismic activity across the Atlantic and is the initial source for any official alert. Emergency officials disseminate the warning through local media, the Emergency Alert System (EAS), and social media platforms.
The local response plan emphasizes two main evacuation methods in the event of a Tsunami Warning. The preferred method is inland evacuation, moving away from the coast to higher ground, with a recommendation to move at least one mile inland. If lead time is insufficient for a mass evacuation, vertical evacuation is advised, which means seeking refuge on the third floor or higher of a tall, structurally sound building.