Another perfect ring in the sky. Its diameter is probably about 100 meters. (Photo: Tom Pfeiffer)
More on VolcanoDiscovery:
Etna's steam rings
: A collection of fantastic vortex rings ("smoke rings") we observed recently on Etna.
Batu Tara photos
: A remote island in the Flores Sea of Indonesia formed by a single volcano that has been in strong strombolian eruption for years. We regularly lead expeditions to there where we camp several days to observe it.
Kelut volcano photos
: A new lava dome grew inside the crater lake during the effusive eruption in late 2007, replacing most of the lake. Watch the birth of a new mountain!
Photos from Kamchatka
: Kamchatka in Russia's far east is one of world's remotest regions and has an almost unparalleled density of active volcanoes. Look at photos taken during our expeditions from this wonderful corner of the world!