Report on Manam (Papua New Guinea) — May 1991
Bulletin of the Global Volcanism Network, vol. 16, no. 5 (May 1991)
Managing Editor: Lindsay McClelland.
Manam (Papua New Guinea) Ash ejection declines to weak vapor emission
Please cite this report as:
Global Volcanism Program, 1991. Report on Manam (Papua New Guinea). In: McClelland, L. (ed.), Bulletin of the Global Volcanism Network, 16:5. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN199105-251020.
Papua New Guinea
4.08°S, 145.037°E; summit elev. 1807 m
All times are local (unless otherwise noted)
". . . Manam has returned to the low non-erupting pattern displayed since early 1989. Both Main and Southern Craters released thin white vapour emissions. Grey ash-laden clouds commonly rose over Southern Crater until 20 May, associated with weak rumbling noises, presumably due to rockfalls within that crater. No night glow was reported from either crater. Tiltmeter measurements showed a slight radial inflation of ~1 µrad."
Geologic Background. The 10-km-wide island of Manam, lying 13 km off the northern coast of mainland Papua New Guinea, is one of the country's most active volcanoes. Four large radial valleys extend from the unvegetated summit of the conical 1807-m-high basaltic-andesitic stratovolcano to its lower flanks. These "avalanche valleys" channel lava flows and pyroclastic avalanches that have sometimes reached the coast. Five small satellitic centers are located near the island's shoreline on the northern, southern, and western sides. Two summit craters are present; both are active, although most historical eruptions have originated from the southern crater, concentrating eruptive products during much of the past century into the SE valley. Frequent historical eruptions, typically of mild-to-moderate scale, have been recorded since 1616. Occasional larger eruptions have produced pyroclastic flows and lava flows that reached flat-lying coastal areas and entered the sea, sometimes impacting populated areas.
Information Contacts: D. Lolok and P. de Saint-Ours, RVO.