Report on Manam (Papua New Guinea) — March 1989
Scientific Event Alert Network Bulletin, vol. 14, no. 3 (March 1989)
Managing Editor: Lindsay McClelland..
Manam (Papua New Guinea) Vapor emission and seismicity continue
Please cite this report as:
Global Volcanism Program, 1989. Report on Manam (Papua New Guinea). In: McClelland, L. (ed.), Scientific Event Alert Network Bulletin, 14:3. Smithsonian Institution. https://doi.org/10.5479/si.GVP.SEAN198903-251020.
Papua New Guinea
4.08°S, 145.037°E; summit elev. 1807 m
All times are local (unless otherwise noted)
"Activity . . . remained at a low inter-eruptive level throughout March. Both Southern and Main Craters released white vapours at weak to moderate rates. Wisps of blue vapour were also released by Crater 2 on 6-9 and 22-27 March. Weak rumbling noises were heard intermittently although no night glow, incandescent ejections, or Vulcanian explosions were reported. Seismicity remained at a normal inter-eruptive level with a daily average of 1,100-1,400 small low-frequency events superimposed on sub-continuous tremor. Tilt measurements showed 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: P. de Saint-Ours and C. McKee, RVO.