Report on Bagana (Papua New Guinea) — May 2006
Bulletin of the Global Volcanism Network, vol. 31, no. 5 (May 2006)
Managing Editor: Richard Wunderman.
Bagana (Papua New Guinea) Lava flows and ash emission throughout March 2006
Please cite this report as:
Global Volcanism Program, 2006. Report on Bagana (Papua New Guinea). In: Wunderman, R (ed.), Bulletin of the Global Volcanism Network, 31:5. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN200605-255020.
Papua New Guinea
6.137°S, 155.196°E; summit elev. 1855 m
All times are local (unless otherwise noted)
Little activity had been recorded at Bagana since 18 September 2005, when forceful emissions of whitish-brown ash occurred, accompanied by ash fall in downwind areas and large booming noises. From the end of January to mid-April 2006 there were brief periods of effusive activity. The summit crater released moderate to dense white vapor throughout this time.
Emissions were forceful on 27 February, and on 3, 5, 7, 13, 22, 24, and 29 March. Denser emissions of pale gray ash clouds were reported on 27 March. Rumbling and roaring noises were heard on 15-16, 22, and 26-28 March. Moderate to bright glow was accompanied by projections of lava fragments and the advance of a lava flow down the S-SW flank, which was visible from 15 March until the end of the month. During April, the summit crater continued to release white vapor. A forceful emission was recorded on 8 April. A weak glow was visible on 9 April. Occasional weak rumbling noises were heard on 12-13 and 15 April. On 4 May, there was an ash plume visible on satellite imagery at a height of ~ 3 km (10,000 ft) altitude that extended 4 km W. On 18 June there was an ash-and-steam plume drifting SW; the height of the plume was not recorded.
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: Ima Itikarai and Herman Patia, Rabaul Volcano Observatory (RVO), P.O. Box 386, Rabaul, Papua New Guinea.