Report on Manam (Papua New Guinea) — November 1987
Scientific Event Alert Network Bulletin, vol. 12, no. 11 (November 1987)
Managing Editor: Lindsay McClelland.
Manam (Papua New Guinea) Strombolian activity
Please cite this report as:
Global Volcanism Program, 1987. Report on Manam (Papua New Guinea). In: McClelland, L (ed.), Scientific Event Alert Network Bulletin, 12:11. Smithsonian Institution. https://doi.org/10.5479/si.GVP.SEAN198711-251020.
Papua New Guinea
4.08°S, 145.037°E; summit elev. 1807 m
All times are local (unless otherwise noted)
Activity remained at the same level in November that it had reached after the moderate increase during the first weeks of October. At Southern Crater a fluctuating night glow accompanied by rumbling noises suggested that Strombolian activity was occurring within the crater. Ejections of incandescent material just over the crater rim were seen on 4 and 16 November. Main Crater emitted a moderate plume of white and blue vapor and displayed a steady night glow 12-27 November. Seismicity showed no significant change, remaining at 1,200-1,400 small-amplitude B-type events/day. Tilt measurements were steady.
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. Lowenstein, RVO.