Report on Manam (Papua New Guinea) — August 1982
Scientific Event Alert Network Bulletin, vol. 7, no. 8 (August 1982)
Managing Editor: Lindsay McClelland.
Manam (Papua New Guinea) Ash clouds, glow at main crater; 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, 7:8. Smithsonian Institution. https://doi.org/10.5479/si.GVP.SEAN198208-251020.
Papua New Guinea
4.08°S, 145.037°E; summit elev. 1807 m
All times are local (unless otherwise noted)
"Main crater erupted impressively from 8 August when thick dark grey ash clouds were emitted and weak to strong crater glow was observed at night. Sharp ejections were seen occasionally. Rumbling and roaring sounds accompanied similar activity until a decline became evident on 23 August. Voluminous blue vapour emissions were seen on several days between 19 and 31 August. Ashfalls in coastal areas were reported on about 30% of days, evenly distributed throughout the month.
"Southern crater activity was very mild during the first half of August. An increase occurred in the second half of the month, and weak to moderate pale grey-brown ash emissions were reported on most days after the 14th. On a few days at mid-month, weak to strong roaring and rumbling sounds were heard from this crater. No Southern crater incandescent activity was observed."
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.