Geology of Santorini

The volcanism of Santorini

An Google Earthv View satellite image shows the Santorini archipel.
An Google Earthv View satellite image shows the Santorini archipel.

Due to the subduction, which is due to the sinking of the African plate under the Euro-Asasian, massive rock masses north of Crete are melted and mixed with heavier magma of the earth's crust. This creates lighter magma that slowly rises in the cracks in the earth's crust. Where there are particularly many faults and cracks, the active volcanic areas of Greece have established in a round zone. The so-called "Aegean arch" begins in the west of Greece with the volcanic areas Loutraki, Sousaki, Methana, Aegina and Poros, then leads via Milos, Kimolos and Polyaegis to Santorini and ends at the islands of Cos and Nisyros. In this area, volcanic eruptions have occurred in historical times and there will also be new eruptions in the future. The potentially most dangerous volcano is that of Santorini with the last eruption in 1950.

Santorini's volcanism began about 2-6 million years ago with undersea eruptions that primarily produced pillow lava. It was only around 900,000 years ago that the first volcanoes slowly reached the surface of the water and formed the volcanoes on the Akrotiri peninsula (red beach, balos, kokkini Petra, etc.).

Then larger stratovolcanoes built up again and again, which were destroyed by later eruptions of newer volcanoes. Again and again there were larger craters that formed the first calderas. There were three devastating, large eruptions, each leaving thick layers of pumice. The last catastrophic eruption was around 1627 BC. BC, which also brought the Minoan culture into the crisis and climate change throughout Europe. The island in the middle of the caldera was destroyed during this time and new islands were only formed by new volcanic eruptions 900 years later.

97 BC Hiéra island first built up, followed by further volcanic eruptions that formed Paléa Kaméni, where AD 726. another massive eruption occurred, leaving the green crater lake behind. Then in 1540 Mikrí Kaméni was formed and slowly expanded to Néa Kaméni through further activity. The last outbreak occurred there in 1950. There was an earthquake crisis in 2011-2012 and the region was raised by up to 9 cm. New magma rose. Since then there has been silence. Time will tell whether this new magma chamber breaks out or simply cools down.