Visual-thermal comparison of Pu‘u ‘Ō‘ō, looking west

Visual-thermal comparison of Pu‘u ‘Ō‘ō crater, looking west. In the normal photograph on the left, large portions of the crater floor are obscured by thick volcanic fume. The thermal image on the right can "see" through this fume, revealing features in the crater. Over the past month, a large portion of the crater floor has subsided. Within this triangular subsidence area, three small lava ponds were active today. Two are visible in this thermal image, while a third (near the South lava pond) is blocked by a steep wall from this angle.