Dazhbog Patera is a volcanic feature on Jupiter's moon Io. This volcano is difficult to differentiate from the other volcanoes and geological features in some images of Io. In images from the Voyager spacecraft, this caldera is quite prominent with its dark reddish floor with a darkish halo around the caldera. (wikipedia entry)
A patera is an irregular crater, or a complex one with scalloped edges. Usually the dish-shaped depression atop a volcano. On Io they are named after words for fire, sun or thunder; volcano gods, heroes, goddesses or mythical blacksmiths.
Image Source. Marker locations are approximate and may not always appear to align with image on map.