Report on Manam (Papua New Guinea) — February 1982
Scientific Event Alert Network Bulletin, vol. 7, no. 2 (February 1982)
Managing Editor: Lindsay McClelland.
Manam (Papua New Guinea) Tephra ejections, ashfalls; increased seismicity
Please cite this report as:
Global Volcanism Program, 1982. Report on Manam (Papua New Guinea). In: McClelland, L. (ed.), Scientific Event Alert Network Bulletin, 7:2. Smithsonian Institution. https://doi.org/10.5479/si.GVP.SEAN198202-251020.
Papua New Guinea
4.08°S, 145.037°E; summit elev. 1807 m
All times are local (unless otherwise noted)
"Weak to moderate ejections of grey or brown tephra from Southern crater were observed on most days. Frequency of eruptions varied, and occasionally they resembled Strombolian activity. Incandescent tephra ejections were visible on the nights of 6, 10, 11, 14, 15, and 17 February. Ashfalls in coastal areas were reported on most days 1-20 February. The only emissions observed from Main crater were white vapours. Seismicity increased during February, and by the end of the month the level was similar to peaks reached in August-September and December 1981. Tilts remained stable."
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.