Report on Manam (Papua New Guinea) — April 1980
Scientific Event Alert Network Bulletin, vol. 5, no. 4 (April 1980)
Managing Editor: David Squires.
Manam (Papua New Guinea) Lava ejections and glow
Please cite this report as:
Global Volcanism Program, 1980. Report on Manam (Papua New Guinea). In: Squires, D (ed.), Scientific Event Alert Network Bulletin, 5:4. Smithsonian Institution. https://doi.org/10.5479/si.GVP.SEAN198004-251020.
Papua New Guinea
4.08°S, 145.037°E; summit elev. 1807 m
All times are local (unless otherwise noted)
"During March, Manam's summit was often obscured by clouds, but when visible, both vents were usually emitting white vapours. Weak rumbling noises were heard on the E side of the volcano on 7 March. Activity strengthened in April, when glow and lava ejections from Southern crater were commonly seen. The highest ejections rose to about 50-60 m above the summit. No eruptions of ash were seen, but white and blue vapours were emitted. A blue haze was occasionally seen in the upper parts of some of the major valleys that descend from the summit. Main crater was usually obscured, but white emissions were observed on a few days. Seismic activity remained at its usual level and tilt readings indicated no trends."
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. [Information Contacts for this and following RVO reports were corrected by the RVO staff in January 1988.]