Marsili is a large undersea volcano in the

Tyrrhenian Sea The Tyrrhenian Sea (, ; or ) , , , , is part of the Mediterranean Sea off the western coast of Italy. It is named for the Tyrrhenians, Tyrrhenian people identified with the Etruscans of Italy. Geography The sea is bounded by the islands of C ...

, about south of

Naples Naples ( ; ; ) is the Regions of Italy, regional capital of Campania and the third-largest city of Italy, after Rome and Milan, with a population of 908,082 within the city's administrative limits as of 2025, while its Metropolitan City of N ...

. The

seamount A seamount is a large submarine landform that rises from the ocean floor without reaching the water surface (sea level), and thus is not an island, islet, or cliff-rock. Seamounts are typically formed from extinct volcanoes that rise abruptly a ...

is about 3,000 m (9,800 feet) tall; its peak and crater are about 450 m below the sea surface. Though it has not erupted in recorded history, volcanologists believe that Marsili is a relatively fragile-walled structure, made of low-density and unstable rocks, fed by the underlying shallow

magma chamber A magma chamber is a large pool of liquid rock beneath the surface of the Earth. The molten rock, or magma, in such a chamber is less dense than the surrounding country rock, which produces buoyant forces on the magma that tend to drive it u ...

. Volcanologists with the Italian

National Institute of Geophysics and Volcanology The National Institute of Geophysics and Volcanology (, INGV) is a research institute for geophysics Geophysics () is a subject of natural science concerned with the physical processes and Physical property, properties of Earth and its surround ...

(INGV) announced on March 29, 2010, that Marsili could erupt at any time, and might experience a catastrophic collapse that would suddenly release vast amounts of magma in an undersea eruption and

landslide Landslides, also known as landslips, rockslips or rockslides, are several forms of mass wasting that may include a wide range of ground movements, such as rockfalls, mudflows, shallow or deep-seated slope failures and debris flows. Landslides ...

that could trigger destructive

tsunamis A tsunami ( ; from , ) is a series of waves in a water body caused by the displacement of a large volume of water, generally in an ocean or a large lake. Earthquakes, volcanic eruptions and underwater explosions (including detonations, la ...

on the Italian coast and nearby Mediterranean coastlines.

Geomorphology

Marsili belongs to the

Aeolian Islands The Aeolian Islands ( ; ; ), sometimes referred to as the Lipari Islands or Lipari group ( , ) after their largest island, are a volcanic archipelago in the Tyrrhenian Sea north of Sicily, said to be named after Aeolus, the mythical ruler of ...

volcanic arc A volcanic arc (also known as a magmatic arc) is a belt of volcanoes formed above a subducting oceanic tectonic plate, with the belt arranged in an arc shape as seen from above. Volcanic arcs typically parallel an oceanic trench, with the arc ...

. It is one of the largest volcanoes in Europe, with a length of and a width of , larger than

Mount Etna Mount Etna, or simply Etna ( or ; , or ; ; or ), is an active stratovolcano on the east coast of Sicily, Italy, in the Metropolitan City of Catania, between the cities of Messina, Italy, Messina and Catania. It is located above the Conve ...

. It was discovered during the 1920s and named after Italian geologist Luigi Ferdinando Marsili. Extensive studies have been carried on only since 2005 as the Italian National Research Council started a vulcanology research program on the site. The volcano rises from a plateau of thin oceanic (or pseudo-oceanic) crust with a thickness of only 10 km, which forms its own sea basin. The basin crust is made of tholeiitic basalt which is most typical of inflated basins at the back of oceanic volcanic arcs. The Marsili basin appears to have formed very recently (2 million years) as a consequence of the growth of the volcanic arc, and Marsili could be the result of the thermal inflation of the thin crust at the center of the basin. The start of the volcano activity could date back as recently as 200,000 years ago. Evidence of lava flows on the mountain flanks was found. Evidence of catastrophic collapses of previous other undersea volcanoes in the same area was also found.

Potential risks

Marsili is an active volcano, with numerous satellite volcanic systems. The magma of Marsili is similar in composition to other volcanoes in the Aeolian Arc. The magma of Marsili came from the Ionian subduction of the seafloor of the

Tethys Ocean The Tethys Ocean ( ; ), also called the Tethys Sea or the Neo-Tethys, was a prehistoric ocean during much of the Mesozoic Era and early-mid Cenozoic Era. It was the predecessor to the modern Indian Ocean, the Mediterranean Sea, and the Eurasia ...

. The volcanic activity started less than 200,000 years ago. Traces of volcanic collapse have been found on the sides of other submarine volcanoes, which may have resulted from tsunamis along the Tyrrhenian coast of southern Italy. Marsili is on a list of the most dangerous submarine volcanoes of the Tyrrhenian Sea, along with Magnaghi, Vavilov, and Palinuro. As with Vavilov, Marsili is at risk of a major collapse from a single event. In addition, hydrogeological deep-water surveys show that there is geothermal activity on Marsili. Marsili has been studied since 2005 as a strategic project of the Italian National Research Council by means of a sonar system and integrated monitoring networks for ocean observations. In February 2010, the research vessel ''Urania'' began a study on the submerged volcano. Considerable instability has been detected. A significantly large region of the Marsili summit is also made up of low-density rocks, strongly weakened by hydrothermal alteration phenomena; which could cause a large collapse event. File:CalabrianArc-GeotectonicSection.jpg, Geological, geotectonic, structural section of the Central Mediterranean Subduction System

References

External links

* {{Authority control Volcanoes of the Tyrrhenian Seamounts of the Mediterranean Volcanoes of Italy VEI-6 volcanoes

Geomorphology

Potential risks

See also

References

External links