Report on Manam (Papua New Guinea) — December 1995
Bulletin of the Global Volcanism Network, vol. 20, no. 11 (December 1995)
Managing Editor: Richard Wunderman.
Manam (Papua New Guinea) Steam release with occasional minor ash and bombs
Please cite this report as:
Global Volcanism Program, 1995. Report on Manam (Papua New Guinea). In: Wunderman, R. (ed.), Bulletin of the Global Volcanism Network, 20:11. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN199512-251020.
Papua New Guinea
4.08°S, 145.037°E; summit elev. 1807 m
All times are local (unless otherwise noted)
Throughout November, Manam's activity remained low and night glow from its craters was absent. On 8 December, weak projections of incandescent lava were seen, and steady glow took place on the nights of 9 and 10 December. During November and December, both summit craters chiefly released steam, but on 8, 17, and 19 November South Crater released wisps of blue vapor, and on 25 and 28 November it released gray ash. South Crater also made weak, low-frequency roaring sounds on 1 November. Except for 6-11 December, activity was low during most of the month.
Earthquakes increased at the end of October, but during November they took place at the moderate rate of 600-1,400/day. They remained moderate in December. In the first half of November a tiltmeter 4 km SW of the summit continued to register slight deflation followed during the latter half of the month by a 2 µrad inflation.
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: Ben Talai, H. Patia, D. Lolok, and C. McKee, RVO.