Report on Manam (Papua New Guinea) — June 1986
Scientific Event Alert Network Bulletin, vol. 11, no. 6 (June 1986)
Managing Editor: Lindsay McClelland.
Manam (Papua New Guinea) More vigorous exlosions; inflation
Please cite this report as:
Global Volcanism Program, 1986. Report on Manam (Papua New Guinea). In: McClelland, L. (ed.), Scientific Event Alert Network Bulletin, 11:6. Smithsonian Institution. https://doi.org/10.5479/si.GVP.SEAN198606-251020.
Papua New Guinea
4.08°S, 145.037°E; summit elev. 1807 m
All times are local (unless otherwise noted)
"In general, Manam's activity was at a low level in June although visible and audible activity increased somewhat in mid-month and a trend of inflationary tilt was observed throughout the month. During the first half of the month both craters displayed a low level of activity, emitting white and blue vapours and occasional low-density ash clouds in small quantities. Weak roaring sounds occasionally emanated from Southern Crater. From the 14th, the content of ash in emissions from both craters appeared to increase, and sharper explosion sounds from Southern Crater were heard until the 19th."
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.