Report on Manam (Papua New Guinea) — 20 October-26 October 2004
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 20 October-26 October 2004
Managing Editor: Gari Mayberry
Please cite this report as:
Global Volcanism Program, 2004. Report on Manam (Papua New Guinea). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 20 October-26 October 2004. 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)
Based on information from JMA, a pilot report, and satellite imagery, the Darwin VAAC reported that an eruption began at Manam on 24 October around 1125, producing a plume to a maximum height of about 15 km (a height of ~6 km was reported in news articles). Preliminary reports from RVO stated that pyroclastic flows traveled down the valley SE of the volcano. The aviation color code was at Red, the highest value. According to RVO, low-level eruptive activity occurred at the volcano after the 24 October eruption and was decreasing by 26 October. News articles reported that authorities advised the evacuation of ~3000 people living near the volcano to safer parts of the island.
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.