Report on Bagana (Papua New Guinea) — December 1989
Scientific Event Alert Network Bulletin, vol. 14, no. 12 (December 1989)
Managing Editor: Lindsay McClelland.
Bagana (Papua New Guinea) Lava overflows crater; rockfalls
Please cite this report as:
Global Volcanism Program, 1989. Report on Bagana (Papua New Guinea) (McClelland, L., ed.). Scientific Event Alert Network Bulletin, 14:12. Smithsonian Institution.
Papua New Guinea
6.137°S, 155.196°E; summit elev. 1855 m
All times are local (unless otherwise noted)
"Mild, sustained, eruptive activity continued throughout December. Numerous rockfalls or avalanches occurred from the unstable blocky flows that slowly spilled over all sides of the summit crater, producing short-lived, red incandescence at night. The seismicity continued to be dominated by rockfall events (several tens/day), with only a few B-type events and occasional swarms of discontinuous tremor (1/2 hour on the 18th and 3 hours on the 21st)."
Geological Summary. 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, RVO.