Report on Manam (Papua New Guinea) — March 1997
Bulletin of the Global Volcanism Network, vol. 22, no. 3 (March 1997)
Managing Editor: Richard Wunderman.
Manam (Papua New Guinea) Activity low with increase near the end of the month
Please cite this report as:
Global Volcanism Program, 1997. Report on Manam (Papua New Guinea) (Wunderman, R., ed.). Bulletin of the Global Volcanism Network, 22:3. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN199703-251020.
Papua New Guinea
4.08°S, 145.037°E; summit elev. 1807 m
All times are local (unless otherwise noted)
During March, Manam was only mildly active and visibility was poor. When visible, the crater was gently emitting a white plume and on two nights there were reports of crater glow. Activity increased slightly during the last week of March. Main Crater had white-to-gray emissions accompanied by occasional weak roaring. Aviation reports noted that at around 1600 on 22 March an eruption plume rose to 3,000 m and drifted SSE. The Tabele water-tube tiltmeter recorded a slight but steady radial inflation.
There was a slow and steady rise in seismicity throughout the month. The number of low-frequency earthquakes increased from ~1,400-1,600 events/day. The amplitude of the events also increased with time.
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: B. Talai, H. Patia, D. Lolok, P. de Saint Ours, and C. McKee, RVO; Bureau of Meteorology, Northern Territory Regional Office, P.O. Box 735, Darwin, NT 0801 Australia.