A rarely seen volcanic eruption on a sub-Antarctic island has been captured by a team of scientists sailing near the remote area.

Heard Island, about 2,500 miles (4,000 kilometers) southwest of Australia and just 600 miles (1,000 kilometers) north of the coast of Antarctica, is about 25 miles (40 kilometers) long and is dominated by an active volcano known as Big Ben. Volcanic activity at the spot has been known since 1881, and satellites recorded eruptions there in the 1990s and 2000s. However, because the island is remote and rarely visited, eye-witness accounts of such eruptions are few and far between.

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Researchers and crew on board the Commonwealth Science and Industrial Research Organisation (CSIRO) ship Investigator witnessed the eruption during a University of Tasmania-led expedition to investigate whether iron from underwater volcanoes in the region exerts control on the dynamics of phytoplankton blooms and fertilization of the Southern Ocean.

“We saw vapor being emitted from the top of the volcano and we saw lava flows coming down the flank of Big Ben,” Professor Mike Coffin of the University of Tasmania’s Institute of Marine and Antarctic Studies, the voyage’s chief scientist, said. “This was a very exciting observation. There are very few ships that come to this part of the world and in fact the last geological expedition that landed on Heard Island was in 1987.”

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Although remote, Big Ben is not the most southerly active volcano in the world. That honor goes to Mt. Erebus, on Antarctica’s Ross Island, which was discovered on January 28 1841, by an expedition led by Sir James Clark Ross.

The volcano was erupting as the expedition’s ships approached, and the juxtaposition of fire and ice moved the ship’s surgeon, Joseph Hooker, to observe that, “this was a sight so surpassing everything that can be imagined … that it really caused a feeling of awe to steal over us, at the consideration of our comparative insignificance and helplessness.”