Report on Ulawun (Papua New Guinea) — 25 June-1 July 2008

Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 25 June-1 July 2008
Managing Editor: Sally Kuhn Sennert

Please cite this report as:

Global Volcanism Program, 2008. Report on Ulawun (Papua New Guinea). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 25 June-1 July 2008. Smithsonian Institution and US Geological Survey.

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Ulawun

Papua New Guinea

5.05°S, 151.33°E; summit elev. 2334 m

All times are local (unless otherwise noted)


RVO reported that increased seismic activity at Ulawun began on 7 June. During 18 June-2 July, mostly moderate-to-strong emissions of white vapor produced plumes that rose from Ulawun and seismometers recorded high-frequency earthquakes. On 22 June, noises heard in villages to the NE accompanied some of the earthquakes. On 28 June, an Intensity II earthquake was felt in areas nearby and accompanied by a booming noise. A team of officers from RVO and West New Britain Provincial Disaster Office informed communities on the activity status of Ulawun. On 30 June, RVO reported that the level of Alert at Ulawun was at "Stage 2", or that there was an increase in seismic activity above background level. During 1-2 July, roaring and jet noises were reported by people to the NE.

Geologic Background. The symmetrical basaltic-to-andesitic Ulawun stratovolcano is the highest volcano of the Bismarck arc, and one of Papua New Guinea's most frequently active. Ulawun volcano, also known as the Father, rises above the north coast of the island of New Britain across a low saddle NE of Bamus volcano, the South Son. The upper 1000 m of the 2334-m-high Ulawun volcano is unvegetated. A prominent E-W-trending escarpment on the south may be the result of large-scale slumping. Satellitic cones occupy the NW and eastern flanks. A steep-walled valley cuts the NW side of Ulawun volcano, and a flank lava-flow complex lies to the south of this valley. Historical eruptions date back to the beginning of the 18th century. Twentieth-century eruptions were mildly explosive until 1967, but after 1970 several larger eruptions produced lava flows and basaltic pyroclastic flows, greatly modifying the summit crater.

Source: Rabaul Volcano Observatory (RVO)