Context: Mount Etna, the largest volcano in Europe, and among the world’s most active and iconic volcanoes, has been sending up almost perfect rings of smoke into the air.
The rings are a rare phenomenon that scientists refer to as volcanic vortex rings, which are produced roughly in the same way as the smoke rings that some cigarette smokers are able to blow out of their mouths
Mount Etna
- Mount Etna, situated on the east coast of Sicily, Italy, is the largest volcano in Europe and one of the most active worldwide.
- Sicily is the largest and most populous island in the Mediterranean Sea and one of the 20 regions of Italy.
- With its summit boasting five craters and numerous flank vents, Etna has been continuously active for centuries, with frequent eruptions both at its summit and along its slopes.
- Designated as a UNESCO World Heritage Site since 2013.
- Etna's eruptive history spans back over 500,000 years, with documented activity for at least 2,700 years.
Vortex Rings
- Volcanic vortex rings, a rare phenomenon, occur when gas, primarily water vapor, is rapidly released through a vent in a volcano's crater.
- These rings, observed above Mount Etna since April 2, 2024, are nearly perfect in shape due to the circular vent opening in the volcano's crater.
- A study suggests that the cold atmosphere above the hot volcano causes water vapour to condense, rendering the rings visible.
Occurrence of Volcanic Vortex Rings:
- In more recent times, volcanic vortex rings have been observed at volcanoes such as Redoubt in Alaska, Tungurahua in Ecuador, Pacaya in Guatemala, Eyjafjallajökull and Hekla in Iceland, Stromboli in Italy, Aso and Sakurajima in Japan, Yasur in Vanuatu, Whakaari in New Zealand, and Momotombo in Nicaragua.
Explanation and Frequency of Rings
- The rings are formed by the explosion of gas bubbles within a narrow conduit, which propels the gas upward at high speeds.
- While not as rare as commonly believed, Etna's frequency of producing these rings surpasses that of any other volcano on Earth.
- Despite their impressive appearance, the presence of these rings does not necessarily indicate an imminent volcanic eruption.