The Galileo spacecraft found many interesting landforms on Jupiter’s moon Io. Included are some that look like volcanoes, with active lava streams.
Several high-temperature volcanic hot spots have been detected in this region by both the Near Infrared Mapping Spectrometer (NIMS) and the solid state (CCD) imaging system on-board Galileo. The temperatures detected in this part of Io are consistent with active silicate volcanism in lava flows or inside irregular depressions called calderas (lava lakes).
The large dark lava flow in the upper left region of the image is more than 400 km long, similar to ancient flood basalts on Earth and mare lavas on the Moon. North is to the top of the picture and the sun illuminates the surface from the left. These pictures were taken by NASA’s Galileo probe on November 6th, 1996, at a range of 245,719 kilometers.