Researchers from the University of Lausanne have proposed a new explanation for the origin of Mount Etna, Europe's most active volcano, challenging the traditional models used to explain how large volcanoes form.

Although Mount Etna is located near a subduction zone where one tectonic plate moves beneath another, the chemical composition of its lava has long resembled that of hotspot volcanoes such as those in Hawaii, creating a geological mystery.The new study suggests that Etna is fed by long-lived pockets of magma located about 80 kilometers (50 miles) beneath Sicily in the upper mantle.

Instead of being generated shortly before eruptions, this magma may have remained stored deep underground for extended periods before being forced upward through fractures created as the African and Eurasian tectonic plates interact.The researchers compare this process to liquid being squeezed from a sponge as the tectonic plate bends and cracks.

By analyzing volcanic rocks spanning approximately 500,000 years of Etna's eruptive history, the team found that the chemistry of its magma has remained remarkably consistent despite changes in the surrounding tectonic environment.

These findings support the idea that the volcano's magma source has been stable over time and that tectonic forces primarily control how much magma reaches the surface.

The authors further propose that Mount Etna could represent the first known large stratovolcano formed through a process similar to that responsible for petit-spot volcanoes, which are typically small submarine volcanic features.

If future research confirms this hypothesis, it would expand current understanding of volcanic formation, introduce a possible fourth category of volcanoes, and improve geological models used to assess volcanic hazards in Sicily and potentially other regions around the world.