Gas Ring Emitted from Mt. Etna

October 02, 2023


Photographer: Rosario Catania
Summary Author: Rosario Catania

Important information on the state of magma inside a volcano comes to us from the gases ejected from craters and fumaroles. The photo at top shows a gas ring emitted on July 18, 2023, from a new crater shaft, which was formed between 16 and 17 July 2023, inside Etna's Bocca Nuova crater, itself formed in 1968.

The photo at center shows the ring that still bears the mark of the crater vent. A gas ring is formed when the gas accelerates in the vicinity of the mouth, after passing through the conduit with different velocities between the center and the rim (slowed down by friction with the walls themselves), assuming a swirling motion, which keeps the rotating gas compressed (ring) until it completely dissolves in the atmosphere.

During outgassing, water, carbon dioxide, sulfur dioxide, hydrogen, carbon monoxide, methane, chlorine, and fluorine compounds, as well as rare gases such as helium, neon and argon are all transported to the surface (bottom photo). 

Mount Etna, Sicily, Italy Coordinates: 37.7490, 14.9799

Related Links:
Mount Etna - Eruption Plume and Scattered Lapilli
Volcanic Gases, Pyroclastic Flow, and Tephra