Report on Ulawun (Papua New Guinea) — October 1998

Bulletin of the Global Volcanism Network, vol. 23, no. 10 (October 1998)
Managing Editor: Richard Wunderman.

Ulawun (Papua New Guinea) White vapor plumes throughout September

Please cite this report as:

Global Volcanism Program, 1998. Report on Ulawun (Papua New Guinea). In: Wunderman, R (ed.), Bulletin of the Global Volcanism Network, 23:10. Smithsonian Institution. http://dx.doi.org/10.5479/si.GVP.BGVN199810-252120.

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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)


A white vapor plume was present throughout September; it appeared to vary in thickness, probably as a result of atmospheric conditions. Observed seismicity was low to moderate. An aerial inspection on 1 October, as part of the Ulawun Decade Volcano workshop, showed the summit crater to be open, ~150-200 m in diameter, with vertical sides descending at least 50 m before being lost in thick white fume.

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. The 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 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 E flanks. A steep-walled valley cuts the NW side, 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.

Information Contacts: Patrice de Saint-Ours, Steve Saunders, and Ben Talai, RVO.