In the Holocene, the process of back-arc extension began, probably stimulated by pressure from the Arabian plate compressing the region behind the arc.

Third, magma broke through the thinned crust to form a second arc composed of a volcanic chain.

And finally, the Aegean Sea plate broke away from Eurasia in the new fault zone to the north.

The active portion of the South Aegean Volcanic Arc comprises a number of dormant and historically active volcanoes, including Sousaki, Aegina, Methana, Milos, Santorini and Kolumbo, Kos, Nisyros and Yali, and Akyarlar.

[1] Of these, only Santorini, Kolumbo, and Nisyros have either erupted or shown any significant evidence of unrest during the past 100 years.