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) (Wunderman, R., ed.). Bulletin of the Global Volcanism Network, 23:10. Smithsonian Institution.
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 N coast of the island of New Britain across a low saddle NE of Bamus volcano, the South Son. The upper 1,000 m is unvegetated. A prominent E-W 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.