Report on Manam (Papua New Guinea) — 10 May-16 May 2017
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 10 May-16 May 2017
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2017. Report on Manam (Papua New Guinea). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 10 May-16 May 2017. 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 during 11-14 May Manam’s Main Crater was quiet, emitting only dense white vapor. On 12 May Southern Crater emitted dark gray ash plumes, and on 13 May only whitish-blue vapor emissions were observed. During 0100-0400 on 14 May roaring and explosions were heard in Bogia Station; incandescent lava fragments were ejected from the crater. Seismicity was low (RSAM averaged 50 units) and dominated by low-frequency events during 11-12 May. RSAM increased on 13 May, peaking at 450 units at 2330, and then dropped to 110 units at 0500 on 14 May. RSAM increased to 250 by 0800 and remained at that level through 14 May. The Alert Level remained at Stage 2.
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)