Report on Manam (Papua New Guinea) — November 1990
Bulletin of the Global Volcanism Network, vol. 15, no. 11 (November 1990)
Managing Editor: Lindsay McClelland.
Manam (Papua New Guinea) Seismicity drops sharply; gas emission
Please cite this report as:
Global Volcanism Program, 1990. Report on Manam (Papua New Guinea) (McClelland, L., ed.). Bulletin of the Global Volcanism Network, 15:11. Smithsonian Institution.
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 in November. Both craters continued to release very weak to moderate emissions of thin white vapour. Additionally, thin blue vapour emissions were observed on two occasions from Main Crater, and brown ash emissions were reported once from Southern Crater. No noises or glow were reported from either crater. The daily total of volcanic earthquakes declined further from an average of ~150 at the end of October to <30 from mid-November to the end of the month. Amplitude of these events was very low."
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 and I. Itikarai, RVO.