Big Ben (Heard Island)
Big Ben is a volcanic massif that dominates the geography of Heard Island in the southern Indian Ocean. It is a stratovolcano with a diameter of about. Its highest point is Mawson Peak, which is above sea level. Much of it is covered by ice, including 14 major glaciers which descend from Big Ben to the sea. Big Ben is the highest mountain in Australian states and territories, except for the Australian Antarctic Territory. The Australian Antarctic Territory is a territorial claim unrecognised by most other countries, meaning that Big Ben is the highest mountain over which Australia has true sovereignty. A smaller volcanic headland, the Laurens Peninsula, extends about to the northwest, created by a separate volcano, Mount Dixon; its highest point is Anzac Peak, at.
Big Ben was first summited on 25 January 1965 by five members of the Southern Indian Ocean Expedition to Heard Island.
Volcanic activity
Big Ben formed about one million years ago. Volcanic activity at the cone has been known since 1881. An eruption occurred in 1993. Satellite images detected eruptions during 2000. On 2 February 2016, observations from Atlas Cove, northwest of Mawson Peak, showed plumes up to high over the volcano. Satellite images showed hotspots at various times from 2003 to 2008, and during September 2012. A further eruption was reported on 2 February 2016, and was recorded by scientists who happened to be in the area on an expedition. Big Ben does not endanger humans because Heard Island is uninhabited.Sentinel-2 satellite imagery suggests another eruption has occurred in May 2023.
Big Ben is in a remote location, and without regular observation it is possible that eruptions have occurred at other times.