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Rare Volcanic Eruption Causes Rapid Growth of Island

Satellite image shows eruption of Montagu Island in the South Sandwich Islands in the South Atlantic. (Image credit: HIGP/BAS)

A rare volcanic eruption is rapidly expanding the size of an island in the South Atlantic, scientists announced today.

New satellite images show that Montagu Island, a volcano in the South Sandwich Islands, has grown by 50 acres (0.2 square kilometers) in the last month as lava pours into the sea.

"Red hot lava has formed a molten river 90 meters wide [99 yards] that is moving fast, possibly several meters per second and extending the shoreline on the north side of the island," said John Smellie of British Antarctic Survey (BAS). "This event is special because Montagu Island is mostly ice covered and it's very rare that we get to make direct observations of eruptions under ice sheets."

Smellie studies Antarctic rock formations to find out how ancient eruptions affected the growth and retreat of ice sheets over the past 30 million years. The research helps climate scientists put modern atmospheric changes into perspective and predict future climate change.

"This opportunity to monitor a live eruption and see how it affects ice cover is priceless," he said.

Researchers thought volcanic activity on Montagu Island, which started in 2001, was winding down. This is the first eruption on the island to be observed as it occurs.

The South Sandwich Island chain is an arc of 11 volcanoes 1,240 miles (2,000 kilometers) from the Antarctic continent. This remoteness means they are relatively pristine, unaffected by continental contamination. 

The chain is home to about two-thirds of the world's breeding population of chinstrap penguins.  Antarctic fur seals also breed there, although neither species currently use Montagu Island because steep rock and ice cliffs surround it.  Several species of moss and soil invertebrates are unique to the area.

Smellie plans to fly over the volcano, part of the British Overseas Territory, early next year to get a better look. 

Robert is an independent health and science journalist and writer based in Phoenix, Arizona. He is a former editor-in-chief of Live Science with over 20 years of experience as a reporter and editor. He has worked on websites such as and Tom's Guide, and is a contributor on Medium (opens in new tab), covering how we age and how to optimize the mind and body through time. He has a journalism degree from Humboldt State University in California.