Report on Manam (Papua New Guinea) — 23 March-29 March 2005
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 23 March-29 March 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, 23 March-29 March 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)
Mild eruptive activity continued at Manam during 22-28 March. Weak-to-moderate emissions from both the Main and Southern craters continued to produce occasional ash clouds during most days. On 24 March, emissions from Main Crater rose to ~1 km above the summit (~9,200 ft a.s.l.). On 28 March, a moderate explosion produced an ash plume to a height of ~1.2 km above the summit (~9,900 a.s.l.). Ash plumes drifted N, depositing ash on the island. Seismic activity fluctuated between low and moderate, with low-frequency earthquakes recorded. Manam remained at Stage 2 Alert Level.
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)