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Report on Manam (Papua New Guinea) — November 1984

Scientific Event Alert Network Bulletin, vol. 9, no. 11 (November 1984)
Managing Editor: Lindsay McClelland.

Manam (Papua New Guinea) Ash-laden emissions; seismicity declines

Please cite this report as:

Global Volcanism Program, 1984. Report on Manam (Papua New Guinea). In: McClelland, L (ed.), Scientific Event Alert Network Bulletin, 9:11. Smithsonian Institution. https://doi.org/10.5479/si.GVP.SEAN198411-251020.

Volcano Profile |  Complete Bulletin


Manam

Papua New Guinea

4.08°S, 145.037°E; summit elev. 1807 m

All times are local (unless otherwise noted)


"No strong eruptive activity took place in October and November, but both craters continued to release ash-laden emissions, usually in small-to-moderate volumes. Summit incandescence was seen only once, from Main crater on 7 October. Daily earthquake totals decreased from about 2,300 at the beginning of October to 1,500 around 19 October and have remained steady since then. Seismic amplitudes declined slightly in early October, then stabilized at about 2-3 times normal. No significant tilts were recorded."

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.