Report on Manam (Papua New Guinea) — September 1988
Scientific Event Alert Network Bulletin, vol. 13, no. 9 (September 1988)
Managing Editor: Lindsay McClelland.
Manam (Papua New Guinea) Ash and vapor emission; weak glow
Please cite this report as:
Global Volcanism Program, 1988. Report on Manam (Papua New Guinea). In: McClelland, L. (ed.), Scientific Event Alert Network Bulletin, 13:9. Smithsonian Institution. https://doi.org/10.5479/si.GVP.SEAN198809-251020.
Papua New Guinea
4.08°S, 145.037°E; summit elev. 1807 m
All times are local (unless otherwise noted)
"The low level of activity that continued in September was characterized by weak to moderate white vapour emissions from the summit craters. The emissions occasionally contained small amounts of grey ash and blue vapour. Weak fluctuating glow from Main Crater was seen on the 6th and 7th and from Southern Crater on the 7th and 8th. On a few days, rumbling sounds from Southern Crater were reported. Seismicity remained at a normal inter-eruptive level with a daily average of 1100 low-frequency events. Tilt measurements were somewhat erratic and no clear trends were evident."
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 P. Lowenstein, RVO.