Report on Manam (Papua New Guinea) — April 1986
Scientific Event Alert Network Bulletin, vol. 11, no. 4 (April 1986)
Managing Editor: Lindsay McClelland.
Manam (Papua New Guinea) Minor vapor and ash emission
Please cite this report as:
Global Volcanism Program, 1986. Report on Manam (Papua New Guinea). In: McClelland, L (ed.), Scientific Event Alert Network Bulletin, 11:4. Smithsonian Institution. https://doi.org/10.5479/si.GVP.SEAN198604-251020.
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 during April. Southern Crater released weak to moderate emissions containing small amounts of grey or brown ash. Main Crater emissions were usually weak white vapours, occasionally coloured with grey ash. The only audible activity was a low roaring heard on 29 April. No crater glows were seen. Seismicity remained about the same as in March. Daily earthquake totals were ~1,500 at the beginning and end of April, dropping to ~1,100 at mid-month. The amplitudes of these events remained at 1-2 times normal inter-eruptive levels. No significant tilt was recorded."
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.