Ground-based astronomers in August 1998 briefly observed a high-temperature eruption at Masubi, confirming Masubi Fluctus' silicate mafic to ultramafic composition.
In each of these cases, the volcanic plumes emanated from different parts of Masubi Fluctus, providing further evidence that dust plumes like the one at Masubi result from the rapid sublimation of surficial sulfur dioxide frost by warm, advancing lava flow fronts, rather than erupting from the primary volcanic vent. Galileo 's cameras also observed a plume deposit form in September 1997.
The camera on Galileo observed a volcanic plume along Masubi Fluctus during the Galileo extended missions, in July/August 1999 and August 2001. The Galileo spacecraft and ground-based astronomers observed volcanic activity at Masubi on several occasions in the late 1990s, but it was not a persistent thermal hotspot. The lava flow associated with the plume was named Masubi Fluctus shortly after the start of the Galileo mission. It was initially designated as Plume 8, but in 1979 the International Astronomical Union formally named it Masubi, after a Japanese fire god called Ho-Masubi. This was the faintest of the plumes on Io observed by the two Voyager spacecraft. The two-lobed shape of the plume deposit may result from the Masubi volcanic plume during Voyager 1 encounter having two sources on the flow field and two eruption columns. These images reveal a lava flow with a V-shaped northern end, associated with the plume source as noted by the dark plume deposit ring surrounding it, and bifurcated southern section. To date, images taken by Voyager 1's Imaging Science Sub-system Wide-Angle Camera shortly before the spacecraft's closest approach to Io have the highest spatial resolution coverage of this volcano at two kilometers per pixel. Voyager discovered a 64 km (40 mi) tall, 177 km (110 mi) wide volcanic dust plume, composed primarily of sulfur dioxide, at the northern end of a 501 km (311 mi) long dark lava flow. The volcano was first observed during the Voyager 1 encounter with the Jupiter system on March 5, 1979.
0 kommentar(er)
