The great erupting volcanoes on Io produce distinctive surface markings. These are three views of Prometheus (P₃). The bright ring on the surface rims the areas of fallout from the plume, and it is probably an area in which sulfur dioxide frost is being deposited on the surface. [260-451]
These views are of Loki (P₂) as seen by Voyager 1. [260-451]
The asymmetric structure of the plume can be seen.
An ultraviolet image has been used to produce a false-color composite; the large ultraviolet halo above the visible-light plume may be due to scattering from sulfur dioxide gas rather than solid particles.