Report on Manam (Papua New Guinea) — February 1987
Scientific Event Alert Network Bulletin, vol. 12, no. 2 (February 1987)
Managing Editor: Lindsay McClelland.
Manam (Papua New Guinea) Weak glow and roaring
Please cite this report as:
Global Volcanism Program, 1987. Report on Manam (Papua New Guinea). In: McClelland, L. (ed.), Scientific Event Alert Network Bulletin, 12:2. Smithsonian Institution. https://doi.org/10.5479/si.GVP.SEAN198702-251020.
Papua New Guinea
4.08°S, 145.037°E; summit elev. 1807 m
All times are local (unless otherwise noted)
"A low level of activity prevailed at Southern Crater during the first half of the month, but between 18 and 24 February deep roaring was heard and seismic amplitudes increased slightly. A weak variable glow from the crater was observed on 22 February, but no significant change was noted in the volume or ash content of emissions. Main Crater continued releasing white vapours at a low rate. Changes in tilt over the month were barely noticeable, although ~1 µrad of radial inflation had taken place in the first two months of 1987. This was consistent with a longer-term inflationary trend of ~5 µrad/year that began in late 1984."
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.