premise: Therasia is in the volcanic island group of Visayas.
hypothesis: Therasia , also known as Thirasía , is an island in the volcanic island group of Santorini in the Greek Cyclades . The Visayas [ vɪ-ˈsaiəz ] or the Visayan Islands ( Visayan : Kabisay-an , [ kabiˈsajʔan ] ; Kabisayaan , [ kabiˈsɐjaʔan ] ) , is one of the three principal geographical divisions of the Philippines , along with Luzon and Mindanao .