Over the last 200 million years, Antarctica’s climate has changed from a long-lived warm period during the age of the dinosaurs, when lush forests covered the land, to progressively cooler climates, to the ice-covered landscape we see today. Antarctica is also home to volcanoes – some of which are still active today. In the nearby South Shetland Islands is a nearly perfectly circular feature – a volcanic caldera, filled in with ocean water. In order to get inside, it requires tricky navigation of a 230-meter wide opening known as Neptune’s Bellows. Early sealers used Deception’s harbor as a base. Nathaniel Palmer, who first explored the island is thought to have seen the Antarctic Peninsula in 1820 from a break in the caldera wall known as Neptune’s Window.
The volcano that formed Deception is still classified as a “restless caldera with a significant volcanic risk.” A violent explosion 10,000 years ago blew about 30 cubic kilometers of molten rock from the island, and the volcano’s summit collapsed to form the now flooded caldera. Eruptions in 1967 forced the evacuation of scientists working at Argentine, British and Chilean research stations – the Chilean one was destroyed. More eruptions in 1969 forced another round of evacuations and damaged the British station. Five station members, the only occupants on the island, escaped the falling volcanic bombs by carrying pieces of corrugated iron over their heads. They were rescued the same day by a helicopter from a Chilean ship. Eruptions continued in 1970 and again in the early 90s. In the present-day, Spanish scientists monitor seismographs on the island for about 3 months each summer.