National Geographic : 1955 Jan
16 Stromboli, World's Most Active Volcano, Spits Slag by Day, Fire by Night During daylight (above) the flying fragments look unimpressive, but at night (opposite) the incandescent lava describes glowing hyperbolas amid clouds of gas. After the first startling crump of an explosion, fragments continue to fall on the crater's slopes with a staccato patter. Outbursts of fragmental viscous lava give vulcanologists the word "strombolian" to describe similar phenomena around the world. Eruptions usually occur every 10 to 12 minutes.