Which Areas of Greece Are at Risk of Tsunamis?

A tsunami wave in Greece could reach up to 10 meters in height—here’s what experts recommend for preparedness and how the early warning system works.

Greece Under the Tsunami Microscope

Four regions in Greece, identified as high-risk tsunami zones, have come under the scrutiny of UNESCO. This follows a recent meeting of European experts, convened by the organization, to assess tsunami threats in the Mediterranean and the North-East Atlantic.

According to experts, a tsunami event in Greece could have widespread regional consequences, not just localized impacts. This highlights the urgent need for authorities to be well-prepared. As part of this effort, UNESCO has proposed a series of actions to officially classify these vulnerable areas as "Tsunami Ready."

A group of 20 scientists gathered last week at UNESCO headquarters in Paris, invited by its Intergovernmental Oceanographic Commission, which represents over 190 countries.

"The goal of the conference was for top scientists—specialists not only in tsunamis but also in seismology, tectonics, marine geology, and related fields—to conduct an in-depth analysis of potential tsunami sources capable of threatening the Mediterranean and North-East Atlantic," said seismologist Gerasimos Papadopoulos, a member of the Governing Board of the Hellenic Mediterranean University and a technical advisor for the meeting’s planning and execution.

High-Risk Tsunami Zones in Greece

During the three-day conference, special attention was given to two major geotectonic structures:

1. The Hellenic Seismic Arc: This arc stretches from the Ionian Sea, encompassing western Peloponnese, Crete, and Rhodes. It marks the convergence boundary between the African and Eurasian tectonic plates, a zone of immense geological tension that frequently generates powerful earthquakes.

2. The Azores-Gibraltar Seismic Zone: This region, extending from the Azores to Gibraltar, has also experienced massive earthquakes and tsunamis in the past.

"A tsunami in Greece could reach up to 10 meters in height and, depending on the coastline’s topography, could penetrate up to three kilometers inland," Papadopoulos explained. "That’s why all this data needs to be integrated with other research programs to assess the tsunami risk for each area more accurately."

He added, "A major tsunami in Greece would impact the entire Eastern Mediterranean. UNESCO is implementing long-term global programs to reduce tsunami risk, offering scientific recommendations that are now transitioning to operational policies."

What Does It Take to Be "Tsunami Ready"?

To receive "Tsunami Ready" certification—akin to the well-known "Blue Flag" designation for beaches—countries must take specific actions, including:

• Educating the public about tsunami risks.

• Defining flood risk zones to determine how far inland a wave could reach.

• Installing clear evacuation route signage to guide residents and visitors in an emergency.

• Providing informational materials to raise awareness.

• Developing comprehensive emergency response plans.

Greece’s Samos island is already officially designated as "Tsunami Ready." This follows the 7.0-magnitude earthquake on October 30, 2020, which triggered a moderate tsunami along its coast.

The Tsunami Early Warning System

Greece is also part of a broader Tsunami Early Warning System in Europe, developed after the devastating 2004 Indian Ocean tsunami. This system involves operational centers across Mediterranean countries, all coordinated by UNESCO.

With rising concerns over seismic activity, preparedness is key. The ongoing efforts by UNESCO and scientific experts aim to ensure that Greece is ready to face potential tsunami threats, protecting both residents and visitors from one of nature’s most powerful forces.