An uptick in seismic activity on the volcanic island of Santorini has raised concerns about a potential eruption.

There are two volcanoes in the area: Nea Kameni, an islet within Santorini’s caldera; and Kolumbo, a submarine volcano about 8 kilometers (5 miles) northeast of Santorini.

There are two volcanoes in the area: Nea Kameni, an islet within Santorini’s caldera; and Kolumbo, a submarine volcano about 8 kilometers (5 miles) northeast of Santorini.