Pele has a volcanic crater, also known a patera, by in size, which lies at the base of the northern tip of the mountain Danube Planum. The patera has multiple floor levels, with a higher north-eastern section and a lower section that consists of an east-west-trending graben. Volcanic activity at Pele, as seen in images taken by Galileo in October 2001 while Pele was on Io's night side, appears to be limited to small thermal hot-spots along the margins of the patera and a more intense thermal emission source within a dark area in the southeast portion of the patera floor. This distribution of activity, combined with Pele's stability as a hotspot in terms of temperature and power emitted, suggests that Pele is a large, active lava lake, a combination of eruption style and intensity of activity not seen elsewhere on Io. The small hotspots seen in the Galileo data represent areas where the crust of the lava lake breaks up along the margins of the patera, allowing fresh lava to become exposed at the surface. The southeastern portion of the patera, an area of dark terrain in Voyager 1 imagery, is the most active region of the Pele volcano, with the most extensive region of hot lava at Pele. This area is thought to be a vigorously overturning lava lake, suggestive of a combination of a large mass flux of lava to the lake from a magma reservoir below the surface and a large mass fraction of dissolved volatiles like sulfur dioxide and diatomic sulfur. Given Pele's brightness at near-infrared wavelengths, activity at this portion of the lava lake may also result in lava fountaining.