Report on Manam (Papua New Guinea) — January 1987
Scientific Event Alert Network Bulletin, vol. 12, no. 1 (January 1987)
Managing Editor: Lindsay McClelland.
Manam (Papua New Guinea) Weak vapor emission; faint glow visible at night
Please cite this report as:
Global Volcanism Program, 1987. Report on Manam (Papua New Guinea). In: McClelland, L (ed.), Scientific Event Alert Network Bulletin, 12:1. Smithsonian Institution. https://doi.org/10.5479/si.GVP.SEAN198701-251020.
Papua New Guinea
4.08°S, 145.037°E; summit elev. 1807 m
All times are local (unless otherwise noted)
Activity remained at a low level throughout January. Southern Crater emitted mostly weak white to grey vapours while Main Crater emitted mostly weak white vapour; grey [emissions were] observed 11-15 January. Deep rumbling was heard on 18, 21, 26, and 27 January at the observation post 4 km from the summit and a weak glow from Southern Crater was visible the night of 26 January. Seismicity dropped steadily from 1,420 to 840 weak events/day 1-17 January and increased steadily from 1,010 to 1,840 events/day 18-31 January. The water tube tiltmeter... showed no significant changes for the month....
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 P. Lowenstein, RVO.