Report on Manam (Papua New Guinea) — October 1990
Bulletin of the Global Volcanism Network, vol. 15, no. 10 (October 1990)
Managing Editor: Lindsay McClelland.
Manam (Papua New Guinea) Weak vapor emission; earthquakes decline
Please cite this report as:
Global Volcanism Program, 1990. Report on Manam (Papua New Guinea). In: McClelland, L. (ed.), Bulletin of the Global Volcanism Network, 15:10. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN199010-251020.
Papua New Guinea
4.08°S, 145.037°E; summit elev. 1807 m
All times are local (unless otherwise noted)
"Activity declined further in October. Both craters intermittently released very weak emissions of thin white vapour. No noises or glow were observed from either crater. The decline in daily earthquake totals . . . continued in October and by the end of the month averaged only ~150 (compared to ~1,200 during former inter-eruptive periods). The amplitude of these events also decreased to a very low level. No significant changes were observed in tilt measurements."
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 and I. Itikarai, RVO.