Deception Island & Half Moon Island

Saturday 21 March 2020

Today we visited two islands in the South Shetland Island archipelago, Deception and Half Moon. It was a cold morning following the overnight snow storm we encountered crossing the Bransfield Straight to reach the South Shetland Islands from the Antarctic Peninsula

A cold view of the entrance channel
called Neptune's Bellows

The lounge kept us warm

The entrance called Neptune's Bellows

Deception Island is an island in the South Shetland Islands archipelago, which has the safest harbours in Antartica. The island, 850Km south of Cape Horn is the caldera of an active volcano and the exposed portion of an active shield volcano about 30Km in diameter.

The island is horseshoe-shaped and opens to the sea through a narrow channel called Neptune's Bellows (so named because the winds are channelled fiercely through the narrow opening to the caldera). The caldera was produced by an explosive eruption 10 thousand years ago and scattered more than 30 cubic Km of molten rock.

The waters inside the caldera - Port Foster

Two major active volcanoes are in Antarctica, Mt Erebus (located due south of New Zealand in the Ross Sea) and Deception Island. Mt Erebus has been erupting over the last few decades, however Deception Island is responsible for the largest known recored eruption in the Antarctic Area.

There is a third possibly active volcano, Buckle Island but the dates of possible eruptions, 1899 & 1939 are doubted by many researchers.


(JamesKavet.net)

Two consecutive volcanic eruptions in 1967 and 1969 went unpredicted – remarkable failures in the history of volcano monitoring. Maybe because you cannot see most of the volcano above the sea, tourists rarely appreciate its hidden destructive potential. Only the Argentinian and the Spanish observatories still exist.

'Cathedral Crags' the Eastern side of the entrance

Whalers Bay the easternmost part of the caldera past Neptune''s Bellows

Deception was officially discovered by the British sealing captain William Smith in 1820 and was subsequently used for such purposes as seal hunting and whaling before finding its modern calling as a site for science and tourism. Now administered under the Antarctic Treaty System in the past it was claimed by the UK, Chile and Argentina, it provides a unique enclosed environment in which to monitor a "volcano under ice". Three countries financed observatories in the 1960s whilst Spain added its own in 2000.

Old abandoned buildings, rusty tanks and equipment along the shore at Whalers' Bay

The island is more than half covered with soot-stained glaciers and ringed by hills, the highest of which is 539m above the sea. Freshwater springs continually drain to both the inner and outer coasts and several lakes are located in the interior.

Seals were all along the shoreline and some didn't like our presence; others didn't seem to notice.

Several graves were either unearthed, moved, or completely buried by the volcanic mudslides. A few are still marked however about 45 souls remain here in anonymity.

The ruins of the base's surviving main timber building, Biscoe House is to the west of the whaling station. It was badly damaged in the 1969 mudslide.

Rusty abandoned parts of equipment were along the shoreline and partially buried in the ground and now covered with snow.

Snowcat treads partially buried in the ground

These tanks originally held whale oil, but were permanently disabled by the British Navy for fear that Germany would establish a naval fueling station during WWII.