Graham Island (; ) is a submerged volcanic island in the Mediterranean Sea near Sicily. It forms the tip of the submarine volcano Empedocles, south of Sicily, which is one of a number of underwater volcanoes known as the Campi Flegrei del Mar di Sicilia.

The island has emerged from sea level four times in recorded history. Seamount eruptions have raised it from the surface before erosion submerged it again. The last prominent appearance occurred in July 1831, when the island emerged above sea level for six months. During that time, a four-way dispute over the island's sovereignty arose, which remained unresolved.

The island is still referenced on marine charts, as its top is only short of breaking the surface; it thus becomes a potentially dangerous hidden obstacle for many seafaring vessels, whose keels most often run deeper than this. Several eruptions have been reported since the 17th century AD. The island is located in a volcanic area known as the Campi Flegrei del Mar di Sicilia (Phlegraean Fields of the Sea of Sicily), in between Sicily and Tunisia in the Mediterranean Sea. Many submarine volcanoes (seamounts) exist in the region, as well as some volcanic islands such as Pantelleria.

1831 appearance

thumb|left|Graham Island guarded by [[HMS Melville (1817)|HMS Melville]]

Graham Island's most recent appearance as an island was in July 1831. The first reports of high seismic activity and/or eruptions occurred during a period spanning from 28 June to 10 July 1831. These reports came from the nearby town of Sciacca. On 4 July, an odour of sulfur spread through the town reportedly in such quantities that it blackened silver.

The eruptions of 1831 resulted in the island increasing in size to about . At its maximum (in July and August 1831), it was in circumference and in height. It sported two small lakes, the larger of which was in circumference and in depth.

  • Spain also declared its territorial ambitions.
  • Last on the scene was Constant Prévost, a co-founder of the French Geological Society, who compared the eruption to a bottle of champagne being uncorked. He named the island Julia, because it was born in July, and probably also in reference to France's July Monarchy.

Diplomatic disputes over the island's status ensued. During the island's brief lifespan tourists began to travel to the island to see its two small lakes.

None of these ideas came to fruition, however, as the island soon sank back beneath the waters. The island was composed of loose tephra, easily eroded by wave action, and when the eruptive episode ended it rapidly subsided, disappearing beneath the waves in January 1832, before the issue of its sovereignty could be resolved. By 17 December 1831, officials reported no trace of it. As dynamically as the seamount appeared, it disappeared, defusing the conflict with it.

In August 1831, observers around the world reported a discolored sun in the sky, tinted blue, purple, or green. Researchers have attempted to discover what volcanic activity was responsible for the stratospheric discharge that caused the discoloration, with an early consensus that Babuyan Claro in the Philippines was the most likely source. Yet, later research has concluded there was no 1831 eruption at Babuyan Claro, and some have argued the smaller activity at Graham was the likely culprit. Even later research ruled out a larger 1831 eruption of the Zavaritski Caldera, as the phenomenon predominated in a limited geographic range and lasted only a month. Nat Turner, an enslaved preacher in Southampton County, Virginia, took the bluish-green sun as a divine sign to begin what became known as Nat Turner's slave rebellion.

Recent seismic activity

right|thumb|A [[seismograph, placed on the former island in 2006, is recovered in 2007]]

Fresh eruptions in 1863 caused the island to reappear briefly before again sinking below sea level. In November 2002 the Institute of Geophysics and Volcanology in Rome observed minor seismic activity and gas emissions.

To forestall a renewal of the sovereignty disputes, in November 2000 Italian divers planted a Sicilian flag on the top of the volcano in advance of its expected resurfacing.

Scientific study

thumb|left|A page out of the field journal of French geologist [[Constant Prévost. Illustrations by a French artist.]]

The sudden geologic phenomenon was observed and studied by numerous scientists. Among the Germans were Hoffmann, Schultz, and Philippi. Among the English were Edward Davy and Warington Wilkinson Smyth. Among the Italians was Scinà Domenico (1765–1837) who published his observations in the "Effeméridi Sicilians" (1832, vol. 2), and Carlo Gemmellaro (1787–1866), teacher of geology and mineralogy at Catania University, who published "Actions of the Gioenia Academy of Catania" (1831, vol.8).

In 2000, an unofficial minting of a penny was produced by a Sicilian artist, featuring the former island on one side and, unusually, a bust of Elizabeth II on the other. David Mannucci, the designer of the coin, had the idea to produce it after he "found out the existence of the ghost island" from a newspaper article. Besides the copper piece, he minted varieties in silver, copper "with protective enamel", and in silver "with protective enamel". While this Italian-made coin fittingly bears the Italian name for the former island, the art coin also features a bust of "Elizabeth II D.G.R." and bears a British denomination.

See also

  • List of islands of Italy
  • List of volcanoes in Italy
  • Campi Flegrei del Mar di Sicilia
  • Volcanism of Italy
  • Sabrina Island (Azores), an earlier volcanic island and diplomatic incident analogous to that of Graham Island
  • Malta Escarpment
  • Palinuro Seamount
  • Calypso Deep
  • Hellenic Trench
  • Mediterranean Ridge
  • Eratosthenes Seamount

References