Report on Bagana (Papua New Guinea) — January 1990
Bulletin of the Global Volcanism Network, vol. 15, no. 1 (January 1990)
Managing Editor: Lindsay McClelland.
Bagana (Papua New Guinea) Continued slow summit lava extrusion; new lava pulses every 4-5 days
Please cite this report as:
Global Volcanism Program, 1990. Report on Bagana (Papua New Guinea). In: McClelland, L. (ed.), Bulletin of the Global Volcanism Network, 15:1. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN199001-255020.
Papua New Guinea
6.137°S, 155.196°E; summit elev. 1855 m
All times are local (unless otherwise noted)
"Mild but steady eruptive activity continued as a result of slow extrusion of blocky lava in the summit crater. The main visible activity consisted of frequent rockfalls of (night-glowing) rock avalanches from the summit onto all flanks of the volcano. New pulses of lava were seen spilling onto the SE flank and into the [1966-75] lava channel at 4-5-day intervals. Abundant fumaroles are present within the crater which is weakly glowing at night. Two low explosions were reported on the 10th and 27th. Seismicity continued to be dominated by rockfall events (several tens/day), but occasional B-type events were also recorded. Seismic monitoring . . . ceased on the 24th, due to the loss of telemetry as the result of the current civil disturbance . . . ."
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: I. Itikarai and P. de Saint-Ours, RVO.