Report on Manam (Papua New Guinea) — 16 August-22 August 2006
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 16 August-22 August 2006
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2006. Report on Manam (Papua New Guinea). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 16 August-22 August 2006. Smithsonian Institution and US Geological Survey.
Papua New Guinea
4.08°S, 145.037°E; summit elev. 1807 m
All times are local (unless otherwise noted)
The RVO reported continuous emissions of ash clouds from Manam's Main Crater during 14-17 August. On 14 August, dense pale gray-to-brown ash clouds rose to less than 1 km above the summit (~9,200 ft a.s.l.) and drifted WNW. During 15-17 August, the emissions decreased to diffuse pale gray ash clouds and weak incandescence was observed at night.
Based on pilot reports and satellite imagery, the Darwin VAAC reported continuous emissions during 17-21 August. The plumes reached altitudes of 3.7 km (12,000 ft) a.s.l. and drifted NW.
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.
Sources: Rabaul Volcano Observatory (RVO), Darwin Volcanic Ash Advisory Centre (VAAC)