The Kameni islands are the cone - still active - of the volcano. A volcanic change took place in the year 726 probably on ‘Palaia Kameni’, and after this violent explosive no further sub-aerial volcanic activity was recorded for more than 800 years. The volcano struck again in 1570 and this activity continued for three years, creating a small dome-shaped island, which called 'Mikri Kameni'. The volcanic activity started again in 1707 and continued for more than four years and by September 1711 had created alongside Mikri Kameni a new island which became known as 'Nea Kameni'.
Between 1866 and 1870 there were further violent eruption, when the island of Afroessa, southwest of Nea Kameni, was formed by masses of boiling lava.