Report on Manam (Papua New Guinea) — July 1992
Bulletin of the Global Volcanism Network, vol. 17, no. 7 (July 1992)
Managing Editor: Lindsay McClelland.
Manam (Papua New Guinea) Weak ash emission and glow
Please cite this report as:
Global Volcanism Program, 1992. Report on Manam (Papua New Guinea). In: McClelland, L (ed.), Bulletin of the Global Volcanism Network, 17:7. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN199207-251020.
Papua New Guinea
4.08°S, 145.037°E; summit elev. 1807 m
All times are local (unless otherwise noted)
"Activity during July remained at the low levels reported for the second half of June. There was weak fumarolic activity through most of July, with white and blue vapours emitted from Southern Crater and mostly white vapours from Main Crater. Weak grey ash from Southern Crater was observed on 22 July.
Weak fluctuating night glow from Southern Crater was seen 20-29 July, due to deep-seated explosive activity. There was no night glow from Main Crater during the month and no audible sounds from either crater. Seismic activity was at a low level throughout July. A slight increase was noted later in the month, probably related to the incandescence and explosive activity. No significant change has been recorded from the water-tube tiltmeter at the Observatory since the beginning of May."
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 and C. McKee, RVO.