Santorini, officially Thira or Thera, is a Greek island in the southern Aegean Sea, about 200 km (120 mi) southeast from the mainland. It is the largest island of a small, circular archipelago formed by the Santorini caldera. It is the southernmost member of the Cyclades group of islands, with an area of approximately 73 km2 (28 sq mi) and a 2021 census population of 15,480. The municipality of Santorini includes the inhabited islands of Santorini and Therasia, as well as the uninhabited islands of Nea Kameni, Palaia Kameni, Aspronisi and Christiana. The total land area is 91 km2 (35 sq mi). Santorini is part of the Thira regional unit.
More than 200 tremors near the island of Santorini have prompted Greek authorities to close schools and tell residents to avoid..