Report on Manam (Papua New Guinea) — June 1990
Bulletin of the Global Volcanism Network, vol. 15, no. 6 (June 1990)
Managing Editor: Lindsay McClelland.
Manam (Papua New Guinea) Intermittent ash-laden clouds and B-type earthquakes
Please cite this report as:
Global Volcanism Program, 1990. Report on Manam (Papua New Guinea). In: McClelland, L (ed.), Bulletin of the Global Volcanism Network, 15:6. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN199006-251020.
Papua New Guinea
4.08°S, 145.037°E; summit elev. 1807 m
All times are local (unless otherwise noted)
"Activity remained at a very low level. The deflationary trend recorded since April by the Tabele Observatory water tube tiltmeter stabilized after mid-May, and seismicity was at a low though irregular level in both amplitude and number of earthquakes. From 3 to 10 June, Main Crater intermittently released ash-laden clouds, accompanied by discrete B-type earthquakes. Deep rumbling sounds were heard on 3 and 4 June. In the second half of the month only wisps of white vapour were released by this crater. Activity at Southern Crater was limited to weak emissions of white vapour throughout 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: P. de Saint-Ours and C. McKee, RVO.