Three underwater volcanoes discovered off Sicily

After a weeks-long deepsea expedition, researchers from several universities around the world have discovered three underwater volcanoes off Sicily’s south-west coast.

According to scientists, the newly discovered volcanoes are at least 6km wide and rise more than 150 metres above the surrounding seabed. They join a series of other volcanic cones discovered in 2019 by the National Institute of Oceanography and Experimental Geophysics (OGS) in the marine area between Mazara del Vallo in the Sicilian province of Trapani and Sciacca, a town in Agrigento.

Dario Civile, a researcher at OGS who took part in the project, said: “We believe this is a very important discovery because it sheds light on unexplored seabed. The Mediterranean has been navigated for millennia, yet, surprisingly, we know very little about its seabed.”

OGS said: “The campaign was conducted onboard the German vessel Meteor and was completed a few days ago with the scanning of previously unexplored seabed along the Sicily Channel taking place between 16 July and 5 August.”

It added that researchers had collected rock samples, including lava deposits, to be analysed in the coming months.

Rock samples collected for analysis. Photograph: M191 (SUAVE)

Civile said: “We have noticed hydrothermal activity in the area but it is still early to understand if these volcanoes are active. We must first analyse their rocks and interpret the high-resolution seismic profiles acquired around them.”

However, Prof Aaron Micallef from Monterey Bay Aquarium Research Institute, the co-chief scientist of the expedition, said that based on the data collected and processed so far, the volcanoes were unlikely to be active.

During the expedition, researchers also discovered the wreck of a 100- x 17-metre ship at a depth of 110 metres on the so-called Nameless Bank (Banco Senza Nome) about halfway between the volcanic island of Linosa and Sicily.

Civile said: “We still don’t know anything about this wreck, and at the moment it is impossible to establish when it dates back.”

Scientists have not definitively ruled out that the volcanoes could be active. Photograph: M191 (SUAVE)

The expedition onboard the Meteor was conducted by Geomar Helmholtz Centre for Ocean Research Kiel (Germany). Other institutes were involved in the research, including the University of Malta and OGS; MBARI, the Monterey Bay Aquarium Research Institute (US); Victoria University of Wellington (New Zealand); and the universities of Birmingham, Oxford and Edinburgh (UK) and Kiel (Germany).

Though undersea eruptions often go unnoticed, more than 1m volcanoes are believed to be underwater, and they are the source of 80% of volcanic activity around the world.

Civile said that, in the past, submarine volcanoes in that specific area had erupted once with the appearance of small islands. Sometimes they emerged from the water and then disappeared into the sea shortly after.

On 18 July 1831, a few miles from the recent discovery, a volcanic island broke the surface of the Mediterranean, 30 miles off the town of Sciacca.

Soon after, Capt Sir Humphrey Le Fleming Senhouse led a British naval party to the summit and named it after the first lord of the admiralty, Sir James Robert George Graham. The king of the Two Sicilies, Ferdinand II, was furious at losing a potentially strategic base and sent a warship to replace the union flag.

A French party also landed and named it Giulia, setting the scene for a three-way war. However, the controversy was destined to end in a few months. By December 1831, the island called by Sicilians Isola Ferdinandea, in honour of Ferdinand II, had disappeared.

In November 2000, Sicilian divers planted a flag on this bubbling underwater volcano to thwart any claims of British sovereignty should it resurface. The descendant of the Bourbon king of Naples were summoned, and a plaque was lowered into the waves. It reads: “It will always be Sicilian.”

This article was amended on 10 August 2023 to correctly credit the images used to the M191 (SUAVE) project team, and to include a comment from Prof Aaron Micallef stating that it is unlikely that the discovered volcanoes are still active; the headline and first paragraph were amended to reflect these comments.