Volcanoes blow smoke rings occasionally. Not all of them, and the ones that do only fire off rings under certain conditions, and it's hard to catch them at it. But observations of the phenomena have been recorded throughout history. Fabio Pulvirenti of the NASA’s Jet Propulsion Laboratory wanted to know why rings were ejected from volcanoes, but was daunted by the unpredictability and ephemeral quality of volcanic smoke rings, so he went to work creating a computer simulation to see what conditions they required.
As a doctoral student of volcanology at the University of Auckland, Benjamin Simons has seen smoke rings at several persistently active volcanoes, including Mount Yasur in Vanuatu. The majority of the rings he saw escaped from skylights, roughly circular natural openings perched above the level of volcanic vents that are open to the “beautiful night glow of magma” below.
When small puffs of volcanic gas were forced through these narrow openings, smoke rings appeared. They rose ponderously, he says, rarely having the power to leave the summit crater before fading away. The results of the new computer model match with Simons’ own observations; the more circular the opening, “the more likely it is to produce a smoke ring,” he says.
National Geographic spells out the conditions that cause a volcano to blow smoke rings as determined by Pulvirenti's research. -via Damn Interesting
(Image credit: Steven W. Dengler)