Report on Manam (Papua New Guinea) — January 1982
Scientific Event Alert Network Bulletin, vol. 7, no. 1 (January 1982)
Managing Editor: Lindsay McClelland.
Manam (Papua New Guinea) Incandescent tephra, ashfalls; inflation
Please cite this report as:
Global Volcanism Program, 1982. Report on Manam (Papua New Guinea). In: McClelland, L. (ed.), Scientific Event Alert Network Bulletin, 7:1. Smithsonian Institution. https://doi.org/10.5479/si.GVP.SEAN198201-251020.
Papua New Guinea
4.08°S, 145.037°E; summit elev. 1807 m
All times are local (unless otherwise noted)
"Dark tephra emissions from Southern crater continued throughout January, although periods of white vapour emission became more common from the 16th. Roaring, rumbling, booming, and thudding sounds were more pronounced in the first half of the month. Incandescent tephra ejections were seen on most nights, occurring at intervals of 1-3 minutes. Ashfalls were reported on the E coast of Manam 7-15, 21-22, and 29-30 January.
"Activity at Main crater was subdued, consisting of weak white and brown emissions. Seismicity declined from a peak between mid-December and early January, and by mid-January seismicity was back to normal levels. Tilts were stable during January following the inflationary phase of December 1981."
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.