Report on Bagana (Papua New Guinea) — September 1988
Scientific Event Alert Network Bulletin, vol. 13, no. 9 (September 1988)
Managing Editor: Lindsay McClelland.
Bagana (Papua New Guinea) Increased lava production feeds new lobe
Please cite this report as:
Global Volcanism Program, 1988. Report on Bagana (Papua New Guinea). In: McClelland, L. (ed.), Scientific Event Alert Network Bulletin, 13:9. Smithsonian Institution. https://doi.org/10.5479/si.GVP.SEAN198809-255020.
Papua New Guinea
6.137°S, 155.196°E; summit elev. 1855 m
All times are local (unless otherwise noted)
"An aerial inspection . . . on 5 September confirmed seismic evidence of increased lava effusion. A new lava lobe was observed on the S side of the one that had been active since September 1987. When the volcano was last inspected in April 1988, only one lobe (~1 km long) was present. It appears that this lobe had not advanced much beyond its April position. The new lobe was fed directly from the summit and its broad, moderately-sloping nose was ~200-300 m beyond the first lobe's terminus. Rockslides on the lobe's edges were observed . . . and pale-brown dust mantled the nose of the lobe, indicating that rockslides were occurring frequently. This observation confirmed seismic evidence of repeated rockslides. The top of the summit lava dome was flat. Voluminous white vapour emissions were fed from diffuse sources on the dome's upper flanks. The emission plume was 10-20 km long."
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.