Report on Ulawun (Papua New Guinea) — 16 June-22 June 2010

Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 16 June-22 June 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, 16 June-22 June 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 during 16-17 June white and gray plumes from Ulawun rose 1 km high. Fine ash fell on the SW, W, and NW flanks. Low rumbling noises were heard from the S and SE flanks, and weak fluctuating incandescence was observed for a brief period of time. On 18 and 19 June, white-to-gray plumes rose from the crater, and roaring noises were reported from the NW flank. Seismicity increased to a high level and was dominated by volcanic tremor. During 19-20 June continuing white and gray emissions produced plumes that rose 1 km. Fine ashfall was seen on the NW and SW flanks. Fluctuating incandescence was seen from the S and SE flanks and occasional low roaring noises were noted. Seismicity declined to moderate levels on 20 June.

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)