The VEI 4 eruption started on 29 March 1947 and ended on 21 April 1948. It is likely that this was both the second greatest lava eruption of Hekla whilst Iceland was inhabited and the second greatest lava eruption in the world in the period 1900-1970. A total lava volume 0.8 km3 was produced with 0.21 km3 of tephra. The height of Hekla was 1,447 m before the eruption, increasing to a maximum of 1,503 m, before dropping to 1,491 m subsequently.