Behold a photo of a massive lava bubble, taken by the United States Geological Survey in 1969.
It's from the long eruption of the Kīlauea volcano in Hawaii, which began on May 24, 1969 and went on for a remarkable 1,774 days.
That bubble above is about 65 feet high, but apparently other bubbles were as huge as 246 feet!
As Smithsonian, via Live Science, reports:
Lava fountains erupt either from isolated vents in lava lakes, or from lava tubes that are penetrated by water, according to the USGS. The formation and expansion of gas bubbles in molten rock pushes powerful streams of lava into the air—typically in a haphazard fashion, with the fountains spurting every which way. It is rare, the USGS notes, for the fountain to take the shape of a dome, like the one seen at Mauna Ulu.
In a 1979 report, the USGS wrote that the dome fountain appeared frequently during the October event, which "lasted for 74 hours, nearly twice as long as any other fountaining episode of the eruption." The report also notes that the dome had a mottled surface, caused by solidified crust getting mixed with liquid lava. As part of the dome slid away, experts could see a lava core inside, indicating that the dome was "not simply a large bubble.
