Io, labeled
Io, labeled The images for this full-disk color view of Io were acquired by Galileo during an encounter on July 2, 1999 using the camera's violet, green, and 756-nm near-infrared filters, on Io's anti-Jovian hemisphere. NASA / JPL / UA / Jason Perry

The image is labeled to show the locations of many of Io's volcanoes: Amirani, Camaxtli, Chaac, Culann, Emakong, Gish Bar, Hi'iaka, Isum, Itzamna, Malik, Marduk, Masubi, Prometheus, Smahash, Thor, Tvashtar, Tupan, Zal, and Zamama. Masubi and Marduk are both actively erupting, producing plumes silhouetted against black space. Many of the others are also very likely in active eruption, but their plumes are not visible against the colorful surface of the moon.