The “swarm” of tens of thousands of earthquakes near the Greek island of Santorini earlier this year was triggered by molten rock pumping through an underground channel over three months, scientists have discovered.They used physics and artificial intelligence to work out exactly what caused the more than 25,000 earthquakes, which travelled about 20km (12 miles) horizontally through the Earth’s crust. They used each of the tremors as virtual sensors, then used artificial intelligence to analyse patterns associated with them.One of the lead researchers, Dr Stephen Hicks from UCL, said combining physics and machine learning in this way could help forecast volcanic eruptions.The seismic activity started to stir beneath the Greek islands of Santorini, Amorgos, and Anafi in January 2025. The islands experienced tens of thousands of earthquakes – many of which were over magnitude 5.0 and could be felt.Many tourists fled, and locals feared that the nearby underwater volcano, Kolumbo, might be about to erupt – or that this was a seismic prelude to a larger earthquake, like the devastating, magnitude 7.7 quake that struck the same region in 1956.The scientists, who published their findings in the journal Science, created a 3D map of the Earth around Santorini. They then mapped the evolving patterns of seismic activity of each tremor and the movement and stress in the crust. This resulted in a detailed model of exactly what drove this months-long seismic swarm.The team found that the event was driven by the horizontal movement of magma – from beneath Santorini and the Kolumbo volcano – through a 30km channel that is more than 10km beneath the seafloor between the two islands of Santorini and Anydros.The researchers estimated that the volume of magma that moved through the crust could have filled 200,00 …
