Report on Ulawun (Papua New Guinea) — 7 July-13 July 2010

Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 7 July-13 July 2010
Managing Editor: Sally Kuhn Sennert

Please cite this report as:

Global Volcanism Program, 2010. Report on Ulawun (Papua New Guinea). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 7 July-13 July 2010. 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 white-to-gray plumes rose less than 500 m from Ulawun during 27 June-9 July, and fine ash fell in areas to the SW, W, and NW. Occasional roaring noises were heard on 28 June and during 5-6 July. A slight increase in seismicity (above moderate levels) indicated by overlapping tremors and Real-time Seismic-Amplitude Measurement (RSAM) values was noted during 5-8 July.

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)