Report on Bagana (Papua New Guinea) — August 1986
Scientific Event Alert Network Bulletin, vol. 11, no. 8 (August 1986)
Managing Editor: Lindsay McClelland.
Bagana (Papua New Guinea) Continued viscous lava extrusion; small explosions
Please cite this report as:
Global Volcanism Program, 1986. Report on Bagana (Papua New Guinea). In: McClelland, L. (ed.), Scientific Event Alert Network Bulletin, 11:8. Smithsonian Institution. https://doi.org/10.5479/si.GVP.SEAN198608-255020.
Papua New Guinea
6.137°S, 155.196°E; summit elev. 1855 m
All times are local (unless otherwise noted)
"The phase of viscous lava extrusion from the summit crater continued into August at a moderate level as evidenced from visual observations and seismicity. Reports suggest that surges of lava into the active flow channel on the N flank took place on 6-7 and 31 August. White to brown emissions were usually quietly released from the crater, which was illuminated by a weak glow at night. Small explosions were reported 17-22 August. Rumbling noises were occasionally heard. Seismicity fluctuated throughout the month from 15 to 75 B-type 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: P. de Saint-Ours and C. McKee, RVO.