Global Volcanism Program | Image GVP-00497
The caldera lake of Billy Mitchell in front of the unvegetated Bagana volcano. The Solomon Sea can be seen in the distance to the SW. Two major explosive eruptions from Billy Mitchell, one about 900 and the other about 370 years ago, produced ashfall that covered most of the N half of Bougainville Island and pyroclastic flow and surge deposits that extend 25 km to the E coast. The younger eruption may have been responsible for formation of the summit caldera.
Photo by Wally Johnson, 1988 (Australia Bureau of Mineral Resources).