Report on Manam (Papua New Guinea) — August 1980
Scientific Event Alert Network Bulletin, vol. 5, no. 8 (August 1980)
Managing Editor: David Squires.
Manam (Papua New Guinea) Ash emission continues
Please cite this report as:
Global Volcanism Program, 1980. Report on Manam (Papua New Guinea). In: Squires, D (ed.), Scientific Event Alert Network Bulletin, 5:8. Smithsonian Institution. https://doi.org/10.5479/si.GVP.SEAN198008-251020.
Papua New Guinea
4.08°S, 145.037°E; summit elev. 1807 m
All times are local (unless otherwise noted)
"Activity during August continued at the same level as that of June and July. Emissions from Southern crater were mostly white vapour and brown ash, but grey ash emissions were observed on 20 August and blue vapours were occasionally seen. Roaring and rumbling sounds were associated with stronger pulses of ash emission. Main crater was obscured most of the time, but on several occasions white vapour emissions were observed. Brown ash emissions from Main crater were observed on 20 August. No crater glows or lava fragment ejections were observed from either crater. Seismicity and tilt remained steady."
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.