Report on Bagana (Papua New Guinea) — April 1987
Scientific Event Alert Network Bulletin, vol. 12, no. 4 (April 1987)
Managing Editor: Lindsay McClelland.
Bagana (Papua New Guinea) Ash emissions and summit glow continue
Please cite this report as:
Global Volcanism Program, 1987. Report on Bagana (Papua New Guinea). In: McClelland, L. (ed.), Scientific Event Alert Network Bulletin, 12:4. Smithsonian Institution. https://doi.org/10.5479/si.GVP.SEAN198704-255020.
Papua New Guinea
6.137°S, 155.196°E; summit elev. 1855 m
All times are local (unless otherwise noted)
The activity level in April appeared similar to that in March. Moderate to strong white, gray, and brown emissions were reported. Summit glow was seen occasionally and was especially bright on 1 April. Seismic recording was patchy in April; recordings were made on only 6 days, down from 16 days in March. Increased seismic activity on 12 and 15 March was followed by a period of stronger activity beginning 27 March that probably persisted through 1 or 2 April. Seismicity was at a low level on 6 April but had increased considerably by 16 April when ~60 events were recorded. Activity then subsided and from 23 to 26 April very few volcanic earthquakes were recorded.
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 and P. Lowenstein, RVO.