Report on Manam (Papua New Guinea) — 26 January-1 February 2005
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 26 January-1 February 2005
Managing Editor: Gari Mayberry
Please cite this report as:
Global Volcanism Program, 2005. Report on Manam (Papua New Guinea). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 26 January-1 February 2005. 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)
RVO reported that an eruption at Manam during the evening of 27 January was more severe than other eruptions that have occurred during the current eruptive period. Debris from the eruption was voluminous and widespread on the island. RVO's monitoring base at Warisi village was completely destroyed by a possible pyroclastic flow, preventing RVO from providing information on the current level of activity. One person was killed by volcanic activity, and about 14 people living in Warisi village were injured.
The Darwin VAAC estimated that the eruption around 2400 on 27 January rose 21-24 km a.s.l. The volcanic cloud was very difficult to track because it was ice rich and mixed with monsoonal storms, but dispersion models and satellite imagery suggested that a mid-tropospheric portion of the cloud spread quickly W over Irian Jaya, while a higher portion of the cloud remained near the eruption site for an extended amount of time. Another large eruption occurred around 2300 on 28 January.
According to news reports, many of the residents of the island who were originally evacuated in November 2004 had returned. There were reports of several houses that had burned down from hot emissions and others collapsed under the weight of ash and pyroclastic material. After the large eruption on 27 January, local authorities planned to evacuate about 2,000 residents.
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.