Report on Manam (Papua New Guinea) — 7 April-13 April 2004
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 7 April-13 April 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, 7 April-13 April 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)
During 15 March to 1 April mild eruptive activity occurred at Manam's Southern Crater, with emissions of brown ash on 17, 18, 27, and 28 March. The ash clouds rose to about 100-300 m above the summit and drifted SE, depositing small amounts of ash in the villages of Boakure and Warisi. Vapor was emitted from Main Crater. During the report period, small low-frequency earthquakes occurred. On 24 March there was a slight increase in the amplitude of volcanic earthquakes, but the overall level of seismicity remained low. RVO advised people to stay away from the four main valleys near the volcano.
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.
Source: Rabaul Volcano Observatory (RVO)