Mount Etna May Stem From a Rare Magma Mechanism, Explaining the Volcano’s Puzzling Origins
Europe’s highest active volcano, Mount Etna, may belong to an obscure group of volcanoes shaped by magma in unorthodox ways. Although Etna offers endless research opportunities, with its eruptions several times a year, scientists have never completely understood how this massive volcano formed.
A new study published in the Geophysical Research Journal: Solid Earth proposed an unexpected explanation for Etna’s origins, explaining that it may have been built by a process observed in underwater “little dot” volcanoes that involves pockets of magma being expelled from fractures in tectonic plates.
The unusual formation of Etna
With a volatile history of eruptions on the Italian island of Sicily, Etna is unlike most other volcanoes. According to the new study, this is because it does not fit neatly into the three main categories of volcanic formation. The three categories are as follows, according to the British Geological Survey:
- First, constructive plate boundary volcanoes form when two tectonic plates move apart, leaving space for materials in the Earth’s mantle to rise and melt.
- The second form deals with destructive volcanoes at plate boundaries. They form when two tectonic plates approach each other. An example of this is subduction zones, where one plate slides beneath another. The water contained in the subducting plate is gradually released, lowering the melting point of the mantle; this generates magma and creates some of the most explosive volcanoes.
- A third type of volcano arises from hot spots in the middle of tectonic plates, where plumes of superheated magma rise from the mantle, forming island chains like Hawaii when a tectonic plate moves above the stationary hot spot.
Etna, however, is not formed primarily by any of these mechanisms. Researchers know this thanks to the chemical composition of the volcano; While Etna is located near a subduction zone, it erupts with lava rich in alkalis and trace elements. This is similar to lava from hotspot volcanism, not volcanoes formed in subduction zones. However, there is no hotspot near Etna.
Learn more: Etna erupts during the holidays, ending an active volcanic year in grand finale
A unique volcanic mechanism
To discover the mysterious origins of Etna, researchers collected samples from the volcano to reconstruct the chemical evolution of its lavas. The results showed that the composition of Etna’s magmas remained virtually the same over the years.
Based on this data, researchers believe that Etna formed in a manner similar to the Petit-Spot volcanoes, first described in 2006 by Japanese geologists. These small underwater volcanoes are found in regions where ocean plates bend and squeeze out magma.
Unlike most volcanoes, where magma forms shortly before an eruption, small-spot volcanoes are powered by pre-existing pockets of magma believed to be in the upper mantle. Mount Etna, the researchers propose, is driven by the same process. Small amounts of magma, about 80 kilometers below the surface, rise from the mantle due to the collision of the African and Eurasian plates.
Continuous volcanism on Etna
Etna has caused volcanic unrest in Sicily since prehistoric times; according to the Smithsonian Institution’s Global Volcanism Program, it has one of the longest records of volcanism in the world, dating back to 1,500 BCE.
More recently, eruptive activity was observed from December 29, 2025 to January 4, 2026, producing ash emissions and lava flows near the Valle del Bove, a valley located on the eastern flank of Etna.
Learn more: A massive magma reservoir comparable in volume to that of Yellowstone discovered under Tuscany
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