Report on Ulawun (Papua New Guinea) — December 1999

Bulletin of the Global Volcanism Network, vol. 24, no. 12 (December 1999)
Managing Editor: Richard Wunderman.

Ulawun (Papua New Guinea) White vapor emissions and low seismicity

Please cite this report as:

Global Volcanism Program, 1999. Report on Ulawun (Papua New Guinea). In: Wunderman, R (ed.), Bulletin of the Global Volcanism Network, 24:12. Smithsonian Institution. http://dx.doi.org/10.5479/si.GVP.BGVN199912-252120.

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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)


After the mild eruption on 19 October, in November the activity at Ulawun reverted to its usual low level, gently releasing variable amounts of vapor. Seismicity was at background levels. Activity remained low in December. Visual observation reports during 1-21 December indicated that summit activity consisted of weak-to-moderate volumes of white vapor emissions. Seismicity remained low with low-frequency earthquakes through 16 December when the seismograph became unoperational.

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.

Information Contacts: I. Itikarai, H.Patia, and F. Taranu, Rabaul Volcano Observatory (RVO), P.O. Box 386, Rabaul, Papua New Guinea (Email: rvo@datec.com.pg).