Volcanic Vortex Rings: Etna's Smoke Show Mystery

Why volcanic vortex rings in news?

Mount Etna, Europe’s most active and iconic volcano, has recently captured the world’s attention with a mesmerizing display – smoke rings billowing from its crater.
These perfect circles, a rare phenomenon known as volcanic vortex rings, have left many wondering: what causes them, and why is Etna particularly adept at producing these smoke shows?

Before delving into the vortex rings, let’s set the stage. Mount Etna, towering over Sicily, Italy, is a restless giant.
As the tallest mountain south of the Alps in Italy, it boasts a long and fiery history.
Five craters at the summit and numerous vents along its slopes have kept Etna in near-constant activity.

Eruptions, both at the summit and flanks, are frequent occurrences, with documented activity dating back at least 2,700 years.
UNESCO even recognized its significance by designating it a World Heritage Site in 2013.

The captivating smoke rings are formed by the rapid release of gas, primarily water vapor, through a vent in the crater.
In Etna’s case, the vent creating these perfect circles adds to the visual spectacle.
Scientific literature points to the first observations of volcanic vortex rings occurring at Mount Etna and its neighbor, Mount Vesuvius, way back in 1724.
Engraved plates from that era serve as a testament to this phenomenon.

While Etna is currently stealing the show, volcanic vortex rings are not exclusive to this fiery giant.
They have graced the skies above volcanoes like Redoubt in Alaska, Tungurahua in Ecuador, and even Iceland’s Eyjafjallajökull and Hekla.
Other notable entries on this list include Stromboli (Italy), Aso and Sakurajima (Japan), Yasur (Vanuatu), Whakaari (New Zealand), and Momotombo (Nicaragua).

The formation of these rings mirrors how dolphins create bubble rings. Rapidly expelled gas, compressed within the volcanic conduit, forms a ring as it exits the vent.
Imagine a puff of air blown through a straw – the concept is quite similar.
These ephemeral creations can last up to 10 minutes in ideal conditions, but strong winds can quickly disrupt their delicate structure.

Volcanologist Boris Behncke, an expert on Etna, suggests it might be. Having observed “dozens of gas rings every day” above Etna in July 2023, he went on to state that no other volcano produces these rings with such frequency.
Behncke attributes this to the specific dynamics within Etna’s conduit.
The explosion of gas bubbles within a narrow channel propels gas at high speed, and friction along the conduit walls creates the perfect conditions for ring formation.

The recent display of volcanic vortex rings at Mount Etna serves as a reminder of the awe-inspiring power and beauty of our planet’s geological forces.
While the phenomenon itself is rare, Etna appears to be a champion in this regard.
Understanding the science behind these smoke rings adds another layer of appreciation to this visual spectacle.
So, the next time you hear about volcanic activity, keep an eye out for these fleeting smoke rings – a testament to the dynamic and fascinating world of volcanoes.