Volcanic explosion on Io
Masubi Volcano Plume on Io
Io: Changes at Pillan Patera
Active Volcanic Plumes on Io.
Volcanic explosion on Io

Volcanic explosion on Io

Courtesy of NASA/JPL

http://photojournal.jpl.nasa.gov/catalog/PIA01971


This historic image of volcanic plume on Io was acquired by Voyager 1 1979 March 4 at 5:30 p.m. (PST) about 11 hours before closest approach to the Jupiter moon. The distance to Io was about 490,000 km (304,000 mi). An enormous volcanic explosion can be seen silhouetted against dark space over Io's bright limb. The brightness of the plume has been increased by the computer as it is normally extremely faint, whereas the relative color of the plume (greenish white) has been preserved. At this time solid material had been thrown up to an altitude of about 160 km (100 mi). This requires an ejection velocity from the volcanic vent of about 1900 km/hr (1200 mi/hr), material reaching the crest of the fountain in several minutes. The vent area is a complex circular structure consisting of a bright ring about 300 km in diameter and a central region of irregular dark and light patterns. Volcanic explosions similar to this occur on the Earth when magmatic gases expand explosively as material is vented. On Earth water is the major gas driving the explosion. Because Io is thought to be extremely dry, scientists at the time this image was acquired were searching for other gases to explain the explosion.