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Inside the February 2025 Santorini–Kolumbo Seismo-Volcanic Crisis
Scientists from the Institute of Earth Sciences (ISTERRE – OSUG, UGA/CNRS/USMB/IRD/Université Gustave Eiffel) provide insights into the February 2025 Santorini–Kolumbo seismo-volcanic crisis in a study published in Nature.
Panoramic view of Santorini from the edge of the crater above Athinios port. © Norbert Nagel
A seismic swarm shook the Greek islands of Santorini and Amorgos in the Aegean Sea for an exceptional duration of 20 days in February 2025. Authorities urged the inhabitants of Santorini to remain vigilant in the face of this unusual situation (schools were closed, large gatherings banned, etc.), leading to a mass departure of the population to the mainland.
Indeed, this region is well known for its intense tectonic activity. Around 1610 BCE, the island of Santorini experienced one of the largest volcanic eruptions in human history, and more recently, in 1956, a magnitude 7.7 earthquake in the Amorgos area triggered a Mediterranean tsunami, with waves reaching heights of 20 meters.
This collaborative study, carried out by more than 30 scientists from 13 research institutes worldwide, reveals a plausible scenario to explain the origin of the crisis. By analyzing seismological, geodetic, and geochemical data, the authors showed that the seismic crisis was most likely triggered by the propagation of a 13-kilometer-long magma dike, which extended from the island of Kolumbo toward the island of Amorgos, stopping about 4 kilometers beneath the seafloor. The scientists further suggest the hypothesis of a shared magma source between the Santorini and Kolumbo volcanoes, located 7 kilometers apart.
Fortunately, this seismic crisis ended with a gradual decrease in activity, but the region is now being closely monitored by scientists to detect the slightest sign of reactivation in advance.
Indeed, this region is well known for its intense tectonic activity. Around 1610 BCE, the island of Santorini experienced one of the largest volcanic eruptions in human history, and more recently, in 1956, a magnitude 7.7 earthquake in the Amorgos area triggered a Mediterranean tsunami, with waves reaching heights of 20 meters.
This collaborative study, carried out by more than 30 scientists from 13 research institutes worldwide, reveals a plausible scenario to explain the origin of the crisis. By analyzing seismological, geodetic, and geochemical data, the authors showed that the seismic crisis was most likely triggered by the propagation of a 13-kilometer-long magma dike, which extended from the island of Kolumbo toward the island of Amorgos, stopping about 4 kilometers beneath the seafloor. The scientists further suggest the hypothesis of a shared magma source between the Santorini and Kolumbo volcanoes, located 7 kilometers apart.
Fortunately, this seismic crisis ended with a gradual decrease in activity, but the region is now being closely monitored by scientists to detect the slightest sign of reactivation in advance.
References :
Isken, M.P., Karstens, J., Nomikou, P. et al. Volcanic crisis reveals coupled magma system at Santorini and Kolumbo. Nature 645, 939–945 (2025).
DOI : 10.1038/s41586-025-09525-7
Scientific contacts :
- Nikolai Shapiro, Research Professor at Grenoble Alpes University, Institute of Earth Sciences (ISTERRE-OSUG)
- Florent Brenguier, Research Professor at Grenoble Alpes University, Observatory of Sciences of the Universe of Grenoble, Institute of Earth Sciences (ISTERRE-OSUG)