Hubby was certainly fascinated by the geological aspects of the Santorini eruption, and certainly the signs of a massive eruption was all around, if you know what to look for. To begin with, the soil on the island was all made of volcanic ash. In fact the ash layer was perhaps 50 metres thick. You can see it in this quarry. All those layers under the buildings are all ash.
The volcano before the eruption must have been very big. Hubby says it would have looked like any other volcano cone, perhaps like the shape of Mount Fuji, but bigger. You can get a taste of the scale of the volcano from various high points on the island.
We could see the shape of the caldera clearly curve around from the village of Pyrgos, which we will visit later.
Whichever way you look at the island, Santorini is certainly impressive.