Inaccessible Island is an extinct volcano (last active six million years ago) with Cairn Peak reaching 449 m. The island is 14 km2 (5.4 sq miles) in area, rising out of the South Atlantic Ocean 45 km (28 mi) south-west of Tristan da Cunha.
It is part of the archipelago of Tristan da Cunha which is part of the overseas territory of the United Kingdom known as Saint Helena, Ascension and Tristan da Cunha.
Along with Gough Island, Inaccessible Island is a protected wildlife reserve and both make up the UNESCO World Heritage Site of Gough and Inaccessible Islands.
History & Expeditions
Inaccessible Island was first accessed in 1652 during a voyage by ‘t Nachtglas, a Dutch ship, 146 years after Tristan da Cunha was first sighted by Portuguese sailors. When mapped by sailors, the newly found island was referred to as “inaccessible” since the crew who landed were not able to travel far into the island. Such challenges have persisted, but several expeditions have gone deeper into the island to uncover more details about its wildlife.
The Stoltenhoff brothers, who came to Inaccessible from Germany in 1871, lived there for several years hoping to make a living sealing on the island and selling their wares to passing traders (forgetting how often — or not — Inaccessible ever had visitors). However, due to the scarcity of food, they needed to be rescued in 1873 during HMS Challenger’s visit to examine the flora and fauna there. The South African author Eric Rosenthal chronicled the Stoltenhoffs’ adventure in his book Shelter from the Spray (published in 1952 in South Africa and currently very rare).
In 1922, Ernest Shackleton’s ship, the Quest, stopped by Inaccessible briefly, and a botanist on board discovered a bird later named (after him) the Wilkins Bunting (Nesospiza wilkinsi).
Norwegian scientists made an expedition in 1938 in which they spent three weeks at Inaccessible, cataloguing plants, birds, and rocks. After World War II, a plan was made to convert Inaccessible into a farm, but it fell through. Another attempt at mapping the island was made during the Royal Society expedition of 1962 to Tristan da Cunha, which took scientists to Inaccessible Island. Like many other explorers before them, the scientists were not able to reach the interior of the island.
Inaccessible Island was declared a nature reserve under the Tristan da Cunha Conservation Ordinance of 1976. Tristan islanders, however, were still permitted to harvest seabirds from the island.
The most successful expedition to Inaccessible Island to date was the 1982 expedition by students and faculty of Denstone College. Staying at the island from October 25, 1982, until February 9, 1983, they made detailed maps of the island, studied its flora, fauna, and geology, and carried out a marking programme on more than 3000 birds.
In 1997, Inaccessible Island’s territorial waters out to 22 km (14 miles) were declared a nature reserve under the Tristan da Cunha Conservation Ordinance of 1976. Currently, only guides from Tristan are allowed to take visiting cruise ships to Inaccessible.
The Geology of Inaccessible Island is difficult to study, owing to the large depth of peat bog which covers the plateau in the centre of the island. Nevertheless, the numerous cliffs afford excellent opportunities to study outcrops. The cliffs and shorelines are the most dynamic parts of the island, due to the nature of the sea and weather. Weathering is high and there is much evidence of slumping.
The cliff section at Blenden Hall appears to have slipped some 70 metres, probably attributable to an earthquake on the island. Much of the shoreline is a product of cliff slumping and the throwing up of material by the sea during storms.
The island is purely volcanic, and appears to have formed around 5 million years ago. Tristan da Cunha is relatively young at 1 million years, and Nightingale Island the oldest in the archipelago at 18 million years old.
The main components of the island are basalt lava flows interbedded with pyroclastic material.
These flows dip gently eastwards throughout the islands, indicating that the volcanic centre was to the west of the present island.
Sub-surface soundings show a large shallow area at this point, supporting the theory.
The western and south-western parts of the island contain intruded masses of trachyte: these structures were injected into the active volcano and subsequently exposed by weathering.
Dykes and sills of the same material can be seen in the south-western part of the island.
Parasitic cones and vents produced pyroclastic materials (e.g. ashes and agglomerates) which can be found around the edges of the island: at Blenden Hall the cliffs have a yellowish appearance due to the weathered ashes. A number of cinder cones are present on the eastern part of the plateau.
Due to poor navigation charts, 19th-century sailing ships had to be guided by islands in waters where their crew did not know much about the currents. Shipwrecks were common; at least 22 have occurred in the region of Tristan da Cunha, and at least three confirmed shipwrecks have occurred off the coast of Inaccessible Island.
The first, and most dramatic, was that of the Blenden Hall, a British ship chartered to the East India Company, which set sail in 1821 with 84 passengers and crew aboard. Intending to sail past Saint Helena, it was carried instead towards Tristan da Cunha due to adverse currents. It ran aground on Inaccessible Island and suffered a broken back, but the forecastle was carried inshore. All but two of those aboard survived the shipwreck, and, subsisting on wild celery, seals, penguins, and albatross, managed to build boats some months later.
The first attempt to sail to Tristan failed, resulting in the loss of six people, but the second attempt alerted the Tristanians to their plight. The remainder were then brought to Tristan, where most of them were later taken away by a brig to Cape Town, South Africa. Later shipwrecks included the wreck of the Shakespeare at Pig Beach in 1883 and the Helen S Lea at North Point in 1897.
The Wreck of the Blenden Hall
The Blenden Hall was a ship of 450 tonnes, built in Southampton (UK) in 1811: she was owned by Captain Alexander Greig and was chartered to the East India Company.
Though she sailed frequently between the UK and India, she was not a purpose-built Indiaman. As voyages in these times were often dangerous, she was armed and had a large far beyond that required to work the ship.
Blenden Hall sailed from Gravesend (Kent) on May 6th, 1821, with a large number of passengers aboard. The ship made good progress through the Bay of Biscay, but was becalmed as they reached the Equator. After crossing the Equator, the ship was carried by currents towards South America: she had to set a South-Westerly course past St Helena , but was then carried towards Tristan da Cunha by adverse currents.
She ran aground on Inaccessible Island in misty conditions at 10 AM on July 22nd, 1821. The ship’s back was broken, but fortunately the forecastle broke away and was carried inshore.
All but two of the 84 passengers and crew survived.
The survivors were now in a terrible condition – cold, hungry, some naked and without shelter. The next few months illustrated many of the worst aspects of human nature – many of the survivors argued, fought, stole, drank and behaved abominably.They managed to eke out a living on wild celery, seals and penguins, though it soon became apparent that they were on an uninhabited island, not Tristan da Cunha , and they began to build boats.
Even this activity provoked arguments, and many small teams began building instead of pooling resources. The first boat to try to reach Tristan was made by the cook and 5 seamen: they were never heard from again.
Later another boat made the attempt, succeeded, and on November 10th, 1821, the islanders on Tristan arrived to rescue them. Once on Tristan they overwhelmed the local population, again behaving badly, and William Glass , the Governor of Tristan was relieved to be rid of them when the Brig Nerinae took away all but 7 of the survivors to Cape Town.
Flora & Fauna
When Corporal William Glass and his family became the first settlers at Tristan da Cunha in 1816, goats and pigs were brought to Inaccessible Island to serve as a source of food. Some domestic animals remained for at least 57 years and helped to keep the Stoltenhoff brothers alive during their expedition, but they have now died out. Cattle, sheep, and dogs were also introduced to the island at various points in the island’s history, none remain.
No land mammals, reptiles, amphibians, butterflies, or snails have recently been found at Inaccessible. The island does have 64 native plant species, including 20 types of flowering plants and 17 species of ferns. In addition, 48 invertebrate species exist on the island, 10 of which were introduced.
Subantarctic fur seals and southern elephant seals have also been seen at the island in increasing numbers, and cetaceans live in the surrounding waters most notably southern right whales and resident population of dusky dolphins.
Inaccessible is perhaps best known for the Inaccessible rail, the world’s smallest living flightless bird.
The island has been identified as an Important Bird Area (IBA) by BirdLife International as a breeding site for seabirds and its endemic landbirds.
Birds for which the IBA is significant include northern rockhopper penguins (up to 27,000 breeding pairs), Tristan albatrosses (2-3 pairs), sooty albatrosses (200 pairs), Atlantic yellow-nosed albatrosses (1100 pairs), broad-billed prions (up to 500,000 pairs), soft-plumaged petrels (up to 50,000 pairs), spectacled petrels, great shearwaters (up to 2 million pairs), little shearwaters (up to 50,000 pairs), white-faced storm petrels (up to 50,000 pairs), white-bellied storm petrels (up to 50,000 pairs), Antarctic terns, Inaccessible rails (up to 5000 pairs), Tristan thrushes and Inaccessible buntings.
Inaccessible Island has been used by the islanders of Tristan da Cunha for several economic purposes. The island has guano deposits and eggs, though due to the difficulty of travelling about the island, the islanders have generally chosen to go to Nightingale Island instead.
However, three company ships fish off the coast of Inaccessible. They are permitted by the Tristan da Cunha Annex Penumbra of 1945 to fish up to 3,000 metres from shore.