Report on Manam (Papua New Guinea) — November 1981
Scientific Event Alert Network Bulletin, vol. 6, no. 11 (November 1981)
Managing Editor: Lindsay McClelland.
Manam (Papua New Guinea) Incandescent tephra; ashfalls
Please cite this report as:
Global Volcanism Program, 1981. Report on Manam (Papua New Guinea) (McClelland, L., ed.). Scientific Event Alert Network Bulletin, 6:11. Smithsonian Institution.
Papua New Guinea
4.08°S, 145.037°E; summit elev. 1807 m
All times are local (unless otherwise noted)
"Visible activity appeared to intensify somewhat in November. Brown or grey emissions from Southern crater were observed on most days, and crater glow or ejections of incandescent tephra were seen on most nights. Sound effects associated with this activity varied from low rumbling to thudding, booming, and occasional detonations. Ashfalls in coastal locations 4-5 km from the summit were reported early in November. Main crater was less active, usually emitting white vapours, although grey and brown emissions were observed on 2 days late in the month. Instrumental readings remained 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: C. McKee, RVO.