Report on Bagana (Papua New Guinea) — May 1989
Scientific Event Alert Network Bulletin, vol. 14, no. 5 (May 1989)
Managing Editor: Lindsay McClelland.
Bagana (Papua New Guinea) Numerous rockfalls from new lava flow
Please cite this report as:
Global Volcanism Program, 1989. Report on Bagana (Papua New Guinea). In: McClelland, L. (ed.), Scientific Event Alert Network Bulletin, 14:5. Smithsonian Institution. https://doi.org/10.5479/si.GVP.SEAN198905-255020.
Papua New Guinea
6.137°S, 155.196°E; summit elev. 1855 m
All times are local (unless otherwise noted)
"Observer reports indicated that the increased level of activity was continuing. Emissions were moderate to strong and consisted of white-grey (with occasional brown) ash and vapour clouds. Ashfalls around the summit area, due to rockfalls from a new lava flow on the S flank, were reported 7-11 and 25 May. Glows from the active lava flow were seen 2-3, 16-17, 22, and 24 May. Rumbling noises, correlating well with rockfalls, were heard 1-5, 12-14, and 23 May.
"Seismic monitoring . . . lapsed at the beginning of May because of an inability to maintain telemetry equipment during the current period of civil disturbance on Bougainville Island."
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: H. Patia and C. McKee, RVO.