Surt is an active
volcano
A volcano is a rupture in the Crust (geology), crust of a Planet#Planetary-mass objects, planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and volcanic gas, gases to escape from a magma chamber below the surface.
On Ear ...
on
Jupiter's moon
The Moon is Earth's only natural satellite. It is the fifth largest satellite in the Solar System and the largest and most massive relative to its parent planet, with a diameter about one-quarter that of Earth (comparable to the width of ...
Io. It is located on Io's Jupiter-facing hemisphere at .
Surt consists of an oblong volcanic pit (known as a ''patera''), in diameter, surrounded by reddish
sulfur and bright
sulfur dioxide deposits to its south and east.
The volcano was first observed in images acquired by the ''
Voyager 1
''Voyager 1'' is a space probe launched by NASA on September 5, 1977, as part of the Voyager program to study the outer Solar System and interstellar space beyond the Sun's heliosphere. Launched 16 days after its twin ''Voyager 2'', ''Voya ...
'' spacecraft in March 1979.
Later that year, the
International Astronomical Union
The International Astronomical Union (IAU; french: link=yes, Union astronomique internationale, UAI) is a nongovernmental organisation with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreac ...
named this feature after
Surtr
In Norse mythology, Surtr (Old Norse "black"Orchard (1997:154). "the swarthy one",Simek (2007:303–304) Surtur in modern Icelandic), also sometimes written Surt in English, is a jötunn. Surtr is attested in the ''Poetic Edda'', compiled in the ...
, a leader of the fire giants of
Norse mythology.
Several eruptions have been observed at Surt since it was discovered by ''Voyager 1''. The first eruption observed by Earth-based astronomers following the discovery of
Ionian volcanism took place at Surt on June 11, 1979, between the ''Voyager 1'' and ''
Voyager 2
''Voyager 2'' is a space probe launched by NASA on August 20, 1977, to study the outer planets and interstellar space beyond the Sun's heliosphere. As a part of the Voyager program, it was launched 16 days before its twin, '' Voyager 1'', o ...
'' flybys.
When ''Voyager 2'' encountered the Jupiter system in July 1979, the eruption appeared to have ceased, but a fresh, -wide plume deposit was observed surrounding Surt.
This plume deposit was suggestive of an active
Pele-type plume at Surt between the two Voyager encounters.
In addition, dark material, thought to be lava erupted during the eruption, was visible within the eastern half of the patera.
When the ''
Galileo'' spacecraft first took images of the area in 1996, the appearance of Surt and the surrounding terrain had reverted to its appearance as seen by ''Voyager 1'', again suggestive of a short-lived eruption.
Surt erupted again on February 22, 2001 in the most powerful volcanic eruption ever observed, in terms of the amount of power (in watts) output by the eruption.
The total power output observed at Surt (7.2–8.4
W) during this eruption nearly matches the average total power output for all of Io's volcanoes. Despite such a violent eruption, few surface changes were observed in conjunction with the eruption in images acquired by ''Galileo'' six months later, suggesting that any changes had largely faded.
Fresh, sulfur-rich, reddish deposits were seen in images acquired by Galileo in August 2001 to the northeast of Surt.
References
{{DEFAULTSORT:Surt (Volcano)
Volcanoes of Io (moon)
Active volcanoes