Report on Bagana (Papua New Guinea) — August 1987
Scientific Event Alert Network Bulletin, vol. 12, no. 8 (August 1987)
Managing Editor: Lindsay McClelland.
Bagana (Papua New Guinea) Ash plume; incandescent rockfalls
Please cite this report as:
Global Volcanism Program, 1987. Report on Bagana (Papua New Guinea). In: McClelland, L (ed.), Scientific Event Alert Network Bulletin, 12:8. Smithsonian Institution. https://doi.org/10.5479/si.GVP.SEAN198708-255020.
Papua New Guinea
6.137°S, 155.196°E; summit elev. 1855 m
All times are local (unless otherwise noted)
A moderately thick white to brown plume was continuously released from the summit crater. Plume emission intensified 14-15 August when incandescent rockfalls down the N and W flanks and strong night glow from the summit were reported. On 29 August the summit crater was reported to be completely filled with a smoking lava dome that continued to feed the long-active lava flow on the N flank. Seismicity remained at a low level throughout the month, with 10-20 rockfall events/day.
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.
Information Contacts: C. McKee, P. de Saint-Ours, and P. Lowenstein, RVO.