Powerful Magnitude 7.5 Earthquake Strikes the South Atlantic Ocean Near Argentina, Prompting Urgent Tsunami Advisory for Antarctica

Published on August 22, 2025

A powerful magnitude 7.5 earthquake struck the South Atlantic Ocean near Argentina, triggering an urgent tsunami advisory for parts of Antarctica. The seismic event, which occurred in the Drake Passage, a region known for its geological activity, prompted immediate warnings due to the potential risk of tsunami waves impacting nearby areas.

Powerful Earthquake Strikes the South Atlantic Ocean, Prompting Tsunami Advisory for Antarctica

On Thursday evening, a powerful earthquake with a preliminary magnitude of 7.5 struck the South Atlantic Ocean, setting off alarm bells across the region. The United States Geological Survey (USGS) initially reported the magnitude as 8.0, but later revised it to 7.5. The quake occurred at 11:16 p.m. local time, approximately 710 kilometers (441 miles) southeast of Ushuaia, Argentina, in the Drake Passage, an area lying between South America’s southern tip and the Antarctic Peninsula.

The earthquake’s epicenter, located at a depth of 10.8 kilometers (6.7 miles), created a seismic event that sent shockwaves through the region. Although the Drake Passage is not known for frequent seismic activity, it is situated within an area that is part of the highly active seismic zone surrounding the Pacific Ocean. In the wake of the quake, Chilean authorities promptly issued a tsunami advisory for certain parts of Antarctica. However, there were no evacuation orders issued for Chile or Argentina, the closest countries to the epicenter.

While the region’s remoteness made immediate damage reports difficult to obtain, no casualties were reported, and the extent of destruction remained unclear at the time. The location of the quake, far from densely populated areas, likely limited its immediate impact. Despite this, the earthquake serves as a stark reminder of the seismic hazards that exist in the region.

The Threat of Tsunamis in the Atlantic Ocean

Although tsunamis are not a frequent occurrence in the South Atlantic, their potential to cause widespread destruction remains a serious concern. Historically, the Atlantic Ocean has experienced some significant tsunami events, including a deadly incident in 1929 when a magnitude 7.2 earthquake triggered a deadly tsunami off the coast of Newfoundland, Canada. That event led to an underwater landslide, which sent a massive wave into the Burin Peninsula, claiming the lives of over 20 people.

The threat of tsunamis is most often associated with subduction zone earthquakes, where massive shifts in tectonic plates displace large amounts of water, generating waves that can travel thousands of kilometers across the ocean. While subduction zone earthquakes are more common in the Pacific and Indian Oceans, the Atlantic has also seen major events capable of producing destructive tsunamis.

The 1929 Newfoundland tsunami is one example of how the Atlantic can experience the devastating effects of seismic activity. Similarly, the 1755 Lisbon earthquake, which was one of the deadliest in European history, produced a massive tsunami that spread across the Iberian Peninsula, Azores Islands, North Africa, and reached as far as the Caribbean, Bermuda, and Newfoundland.

The Risk of Underwater Landslides

Recent studies suggest that underwater landslides pose the greatest risk for generating tsunamis in the Atlantic. These landslides can trigger localized tsunamis, but in some cases, large-scale events can produce basin-wide hazards. Key areas where underwater landslides could generate tsunamis include the continental slopes off the eastern U.S. and Canada, the Puerto Rican Trench, and the Storegga Slides off Norway’s coast.

These events, though rare, have the potential to create large waves that could affect coastal communities thousands of miles away from their origin. The geological features of these areas suggest that they could act as sources for significant underwater landslides, which could in turn result in destructive tsunamis.

The Canary Islands: A Potential Tsunami Risk

Another potential tsunami risk in the Atlantic is linked to volcanic activity in the Canary Islands, specifically the possibility of a catastrophic collapse of the western flank of the La Palma volcano. If such an event were to occur, it could trigger a tsunami with waves ranging from 1 to 3 meters, which could impact the U.S. East Coast. Although this scenario is considered unlikely, its potential consequences highlight the need for preparedness in the region.

While the Atlantic Ocean is less prone to the “megathrust” earthquakes typically seen in regions like Japan or Indonesia, powerful seismic events in the region can still lead to significant hazards. In the event of a repeat of the 1755 Lisbon earthquake, for example, tsunami waves of up to 3 meters could impact the coastline of Atlantic Canada, a reminder of the region’s vulnerability to seismic activity.

A Growing Focus on Seismic Awareness

As scientific research and understanding of seismic hazards in the Atlantic Ocean continue to evolve, it becomes increasingly clear that regions like the Drake Passage, the continental slopes, and areas around the Canary Islands need to be closely monitored. While the immediate impact of the recent 7.5 magnitude earthquake appears to be limited, the potential for larger seismic events in the future cannot be ignored.

A powerful magnitude 7.5 earthquake struck the South Atlantic Ocean near Argentina, sending shockwaves through the region. Occurring in the seismically active Drake Passage, the earthquake prompted an urgent tsunami advisory for parts of Antarctica. Authorities quickly issued warnings, urging caution in the wake of the seismic event.

The tsunami advisory issued for Antarctica in the wake of the quake is a stark reminder that tsunamis are a genuine threat in the South Atlantic and could impact countries along the coastlines of South America, North America, and even parts of Europe and Africa. Local authorities and international agencies must continue to assess seismic risks and prepare for the possibility of future events that could disrupt the region and the surrounding coastal communities.