A major international marine geophysical mission led by the Institute of Marine Sciences in Barcelona, part of ICM-CSIC, and the National and Kapodistrian University of Athens has gathered critical new data on earthquake and tsunami risks in Greece’s Ionian Sea.
The expedition, known as ODISSEY, surveyed waters off the Ionian Islands, including Corfu, Zakynthos, and Kefalonia, as well as areas near the Peloponnese. The campaign marked the second part of the research mission and ranks among the most extensive marine geophysical surveys ever conducted in Greek waters.
The team focused on one of the Mediterranean’s most seismically active regions, where strong earthquakes have repeatedly affected coastal communities. ODISSEY aims to clarify how the area’s tectonic plate-subduction system works and to improve understanding of the complex geodynamic setting beneath the seafloor.
ODISSEY mission maps earthquake risks in Greece’s Ionian sea
During the mission, scientists compiled high-resolution seismic reflection profiles for more than 2,200 kilometers (1,367 miles). The dataset provides a detailed image of the Earth’s crust beneath the seabed and a clearer view of underwater structures linked to seismic activity that can be utilized in future studies.
High-resolution seismic imaging formed the core of the expedition. The team used advanced marine survey equipment, including eighteen airguns and a three-kilometer (1.8-mile) streamer with 240 hydrophones, to examine the structure and movement of major faults at depth.
Researchers placed particular emphasis on faults with the potential of generating major earthquakes. By identifying their geometry and behavior, they aim to better comprehend how seismic tension builds up and gets released in the Ionian region.
Studying earthquake and tsunami risks
ODISSEY went beyond mapping the seafloor and deep geological structures. The mission also examined the elastic properties of rocks involved in coseismic deformation, the movement that occurs during an earthquake. This information helps scientists model how faults slip and earthquake energy spreads. It also allows them to assess how specific fault movements could trigger tsunamis, offering a more complete picture of marine hazards in Western Greece.
The findings will support marine geohazard mapping and contribute to increased accuracy in seismic-risk assessments for the Ionian Sea and the wider Mediterranean.
Seafloor instruments to construct 3D model
As part of the broader ODISSEY program, researchers deployed eighteen ocean-bottom seismographs during the first phase of the mission. These instruments will remain on the seafloor for a year, collecting data from beneath the Ionian Sea.
The third phase is scheduled for July 2026, when researchers are expected to deploy and recover seventeen additional ocean-bottom seismographs along predetermined routes. Data from these instruments will help create a three-dimensional seismic tomography model of the study area. That model will allow scientists to examine the region’s deeper structure with greater accuracy and improve their understanding of the processes that drive seismic activity.
Θαλάσσια Γεωφυσική Αποστολή «ODISSEY»: Αποκάλυψη Κρίσιμων Νέων Δεδομένων για τη Σεισμική Δραστηριότητα στο Ιόνιοhttps://t.co/bhJOLJPxsC pic.twitter.com/MK1ImwpPqy
— University of Athens (@uoaofficial) July 3, 2026
From scientific data to disaster preparedness
The data collected during ODISSEY will play a vital role in improving earthquake and tsunami preparedness. A clearer understanding of the Ionian Sea’s geodynamics can guide researchers in establishing more effective parameters for civil protection planning and disaster-risk reduction.
According to the scientific team, the characterization of offshore geological structures represents one of marine geophysics’ most significant contributions to society. The results are expected to build on practical knowledge that can assist in the reduction of marine geohazards and protection of coastal communities across the Mediterranean.
The project also aligns with the research priorities of Spain’s Strategy for Science, Technology and Innovation 2021–2027, particularly its focus on protection from emerging security threats.
International mission in Greece maps earthquake risks beneath Ionian Sea
The Spanish research vessel R/V Sarmiento de Gamboa played a prevalent role in the expedition in conjunction with technical support from the Marine Technology Unit of Spain’s National Research Council. The mission brought together researchers and institutions from numerous countries.
It involved cooperation with CNR-ISMAR, the Institute of Marine Sciences of Italy’s National Research Council, and GEOMAR Helmholtz Centre for Ocean Research Kiel in Germany. Greek support came from the Hellenic Hydrocarbons and Energy Resources Management Company and the Hellenic Navy Hydrographic Service.
Dr. Manel Prada of the Institute of Marine Sciences in Barcelona led the international team, while Professor Paraskevi Nomikou of the National and Kapodistrian University of Athens served as co-principal investigator.
During the mission, the University of Athens research team also joined World Hydrography Day activities through a live connection with an event organized by the Hellenic Navy Hydrographic Service, highlighting the importance of hydrography and marine research for public safety, coastal resilience, and communities in general.
See all the latest news from Greece and the world at Greekreporter.com. Contact our newsroom to report an update or send your story, photos and videos. Follow GR on Google News and subscribe here to our daily email!
