Because the volcano at Santorini collapsed into itself, the island now has a funny shape. You can still see a main island that is Santorini in the shape of a backwards “C”, and you can see some small islands nearby. If you look closely, you can see that Santorini and the islands of Therasia and Aspronisi seem to make a circle. They are part of the rim of a large volcanic crater. The main part of the volcano is on the ocean floor, but some parts are tall enough to stick up above the ocean, and those are the islands we see. The islands are a part of a huge rim of the large crater that has already collapsed. This caldera is underwater. My friend tells me that not all calderas are under water. Some volcanoes on land also collapse like this.

Two of the smaller islands, in the middle, are actually newer islands. First, an eruption in 46 A.D. created the islet called “Palea Kameni”. Another eruption in 1570 lasted three years and created a small island called “Nea Kameni”. Little islands are created as lava comes through the floor of the caldera underwater and pushes high enough to form a new landmass.

Though there have been periods of inactivity at Santorini as long as 135 years and 800 years, once in a while one of the islets will erupt. The last eruption in this group of islands was in 1950 on the islet of Nea Kameni. I have to wonder when the next one will happen!