Report on Manam (Papua New Guinea) — 3 October-9 October 2018
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 3 October-9 October 2018
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2018. Report on Manam (Papua New Guinea). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 3 October-9 October 2018. 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 on 1 October field observations after an eruption at Manam confirmed lava flows in the NE valley. There were two lava flow lobes, both stopping before inhabited areas; the smaller lobe flowed on the N side of the valley towards Koland Village and the larger flowed on the S side towards Boakure Village. Effects from ash and scoria fallout on the NW and NW sides of the island were minor. Based on analyses of satellite imagery and wind model data, the Darwin VAAC reported that on 3 October an ash plume rose 2.1 km (7,000 ft) a.s.l. and drifted NW. A thermal anomaly was also visible.
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)