Author name: Timothy H. Druitt

The Late Bronze Age eruption of Santorini occurred 110 km north of Minoan Crete (Greece). Having discharged between 48 and 86 km3 of magma and rock debris, the eruption ranks as one of the largest of the last 10,000 years. On Santorini, it buried the affluent trading port of Akrotiri. Modern volcanological research has reconstructed the eruption and its regional impacts in detail, while fifty years of archaeological excavations have unraveled the events experienced by the inhabitants of Akrotiri during the months that led up to the eruption. Findings do not favour a direct relationship between the eruption and the decline of the Minoan civilization, although tsunamis and atmospheric effects may have weakened Cretan society through impacts on shipping, trade and agriculture.

Santorini Volcano is an outstanding natural laboratory for studying arc volcanism, having had twelve Plinian eruptions over the last 350,000 years, at least four of which caused caldera collapse. Periods between Plinian eruptions are characterized by intra-caldera edifice construction and lower intensity explosive activity. The Plinian eruptions are fed from magma reservoirs at 4–8 km depth that are assembled over several centuries prior to eruption by the arrival of high-flux magma pulses from deeper in the sub-caldera reservoir. Unrest in 2011–2012 involved intrusion of two magma pulses at about 4 km depth, suggesting that the behaviour of the modern-day volcano is similar to the behaviour of the volcano prior to Plinian eruptions. Emerging understanding of Santorini’s plumbing system will enable better risk mitigation at this highly hazardous volcano.

Volcanism along the South Aegean volcanic arc began about 4.7 Ma and has lasted until the present day, with eruptions at Methana, Milos, Santorini, Kolumbo and Nisyros volcanoes in historical times. These volcanoes can be grouped into five volcanic fields: three western fields of small, mostly monogenetic edifices, and two central/eastern fields with composite cones and calderas that have produced large explosive eruptions. Crustal tectonics exerts a strong control over the locations of edifices and vents at all five volcanic fields. Tephra and cryptotephra layers in deep-marine sediments preserve a continuous record of arc volcanism in the Aegean as far back as 200,000 years. Hazards from the volcanoes include high ash plumes, pyroclastic flows and tsunamis. Monitoring networks should be improved and expanded.