In 1707 an undersea volcano breached the sea surface, forming the current centre of activity at Nea Kameni in the centre of the lagoon, and eruptions centred on it continue—the twentieth century saw three such, the last in 1950. Santorini was also struck by a devastating earthquake in 1956. Although the volcano is dormant at the present time, at the current active crater (there are several former craters on Nea Kameni), steam and carbon dioxide are given off.