The island was formed in a volcanic eruption which began 130 meters below sea level, and reached the surface on 14 November 1963. The eruption lasted until 5 June 1967, when the island reached its maximum size of 2.7 km2.
Since then, wave erosion has caused the island to steadily diminish in size, as of 2012, its surface area was 1.3 km2.The most recent survey on 2007 shows the island’s maximum elevation at 155 m above sea level.
The new island was named after Surtr, a fire jötunn or giant from Norse mythology. It is estimated that Surtsey will remain above sea level for another 100 years.