Strange volcanic crater accessible by boat

Antarctica's Deception Island is a semi-submerged volcanic crater that attracts sailors, researchers, and tourists alike.

Deception Island provides shelter for sailors exploring the Southern Ocean. Photo: NASA/Landsat/Lauren Dauphin

The unique shape of Deception Island, Antarctica, is clearly visible in satellite images. This is an active, semi-submerged volcanic crater formed by one of the largest eruptions in the region's history.

Deception Island is currently a shelter for ships and researchers exploring the Antarctic. The horseshoe-shaped island, about 14.5 km wide, is located in the Southern Ocean, about 105 km off the coast of Antarctica. It is part of the South Shetland Islands in the middle of the Drake Passage - a body of water known as the "iceberg graveyard" due to the large number of giant icebergs that have broken away from the Antarctic ice sheet while passing through the strait.

Deception Island gets its interesting name because from sea level, people often mistake it for a solid landmass surrounded by steep cliffs. But when approaching, ships will find a 500m wide gap in the crater rim. This gap, called Neptune's Bellows, leads to a giant hidden lagoon inside.

Explorers first discovered the secret entrance in 1820. Before that, many sailors may have passed through without knowing that it was an ideal shelter to wait out the Southern Ocean's great storms. This shelter was called Foster Harbor.

Deception Island was formed after a massive volcanic eruption about 4,000 years ago, releasing an estimated 30 to 60 cubic kilometers of ash and magma, equivalent to 120 to 240 million Olympic swimming pools. Experts believe it was the largest eruption in Antarctica in at least 12,000 years, according to NASA's Earth Observatory.

The island remains volcanically active, having had at least 20 minor eruptions since the late 19th century. However, it has not erupted since 1970 and has been “quiet” since 2015, when seismic activity was last recorded on the island, according to the Smithsonian Institution’s Global Volcanism Program. There is only one other active volcano in Antarctica – Mount Erebus on Ross Island.

Tourists come to Deception Island to enjoy the hot tubs on the beach. Photo: Lyubomir Ivanov/Apcgb/Wikimedia

Foster Harbour currently hosts two long-term research stations operated by Argentina and Spain, according to the British Antarctic Survey (BAS). A third station, operated by Chile, was destroyed in an eruption in 1970.

Between 50,000 and 100,000 pairs of chinstrap penguins ( Pygoscelis antarcticus ) live on the island, along with a number of seals and other seabirds, according to the BBC . The island is also visited by thousands of tourists each year. They arrive by cruise ship and come ashore to enjoy the hot springs along the beaches of Foster Harbor.