Report on Bagana (Papua New Guinea) — 17 August-23 August 2005
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 17 August-23 August 2005
Managing Editor: Gari Mayberry
Please cite this report as:
Global Volcanism Program, 2005. Report on Bagana (Papua New Guinea). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 17 August-23 August 2005. Smithsonian Institution and US Geological Survey.
Papua New Guinea
6.137°S, 155.196°E; summit elev. 1855 m
All times are local (unless otherwise noted)
During 15-21 August, volcanic activity at Bagana remained at low levels. Variable amounts of thick "white vapor" were emitted from the summit crater. During several nights, dull-to-moderately bright incandescence was visible. On the 20th, lava flowed from volcano's main crater. Incandescent lava avalanches occasionally originated from unstable areas of the lava flow.
Geologic Background. Bagana volcano, occupying a remote portion of central Bougainville Island, is one of Melanesia's youngest and most active volcanoes. This massive symmetrical cone was largely constructed by an accumulation of viscous andesitic lava flows. The entire edifice could have been constructed in about 300 years at its present rate of lava production. Eruptive activity is frequent and characterized by non-explosive effusion of viscous lava that maintains a small lava dome in the summit crater, although explosive activity occasionally producing pyroclastic flows also occurs. Lava flows form dramatic, freshly preserved tongue-shaped lobes up to 50 m thick with prominent levees that descend the flanks on all sides.