Report on Manam (Papua New Guinea) — 24 August-30 August 2005
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 24 August-30 August 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, 24 August-30 August 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 August, with occasional emissions of weak-to-moderate ash plumes on several days. Ash clouds emitted on 22 and 26 August rose several hundred meters above the volcano's crater and drifted NW, depositing ash in areas between the towns of Jogari and Kuluguma, and beyond to Boisa Island. Manam remained at Alert Level " Stage 1."
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.