Report on Balbi (Papua New Guinea) — August 1995
Bulletin of the Global Volcanism Network, vol. 20, no. 8 (August 1995)
Managing Editor: Richard Wunderman.
Balbi (Papua New Guinea) Profuse steaming from the summit amphitheater
Please cite this report as:
Global Volcanism Program, 1995. Report on Balbi (Papua New Guinea). In: Wunderman, R. (ed.), Bulletin of the Global Volcanism Network, 20:8. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN199508-255010.
Papua New Guinea
5.92°S, 154.98°E; summit elev. 2715 m
All times are local (unless otherwise noted)
Aerial inspection was carried out on 22 August, after the 16 August, M 7.8 earthquake that struck 100 km to the W. The inspection revealed profuse white vapor coming from large-output fumaroles in the main fumarole field of the stratovolcano's summit amphitheater. In contrast, emissions at Crater B were moderate and from diffused sources.
Recent landslides were noted in two of the summit craters. The more extensive slides were on the W wall of Crater B. These landslides were thought to have been caused by shaking during the 16 August earthquake.
In general, the visible activity at Balbi appeared to be similar to that observed during previous inspections in the late 1980's. However, emissions may have been more voluminous in 1995.
Balbi marks the highest point on Bougainville Island, forming a summit composed of coalesced cones and lava domes and hosting a large solfatera field. Interviews with local inhabitants suggested that Balbi's last eruption took the lives of a number of people in about 1800-1850.
Geologic Background. The large Balbi stratovolcano forms the highest point on Bougainville Island. The summit of the complex andesitic volcano is part of a large number of coalesced cones and lava domes. Five well-preserved craters occupy a NW-SE-trending ridge north of the summit cone, which also contains a crater. Three large valleys with steep headwalls dissect the flanks. The age of the most recent eruption is not known precisely. An oral tradition of a major eruption during the 19th century is now thought to be in error, but could refer to minor eruptive activity from this relatively youthful-looking volcano. Fumaroles are located within 600-m-wide Crater B and on its W flank.
Information Contacts: Patrice de Saint-Ours and Ben Talai, RVO.