Report on Manam (Papua New Guinea) — April 1989
Scientific Event Alert Network Bulletin, vol. 14, no. 4 (April 1989)
Managing Editor: Lindsay McClelland.
Manam (Papua New Guinea) Incandescent ejections and vapor release
Please cite this report as:
Global Volcanism Program, 1989. Report on Manam (Papua New Guinea). In: McClelland, L (ed.), Scientific Event Alert Network Bulletin, 14:4. Smithsonian Institution. https://doi.org/10.5479/si.GVP.SEAN198904-251020.
Papua New Guinea
4.08°S, 145.037°E; summit elev. 1807 m
All times are local (unless otherwise noted)
"Activity remained at a low inter-eruptive level during April. Both Southern and Main Craters released white vapours at weak to moderate rates. Blue vapour was also emitted from Southern Crater on 9, 13, and 22-23 April. Weak deep rumbling sounds from Southern Crater were heard occasionally 11-30 April. The summit was obscured by clouds on most nights, but during clear conditions on the 11th, glow and weak ejections of incandescent lava fragments were observed above Southern Crater. Volcano-seismicity remained at a normal inter-eruptive level with daily earthquake totals ranging between ~700 and 1,200. Tilt measurements showed no trends."
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: C. McKee, RVO.