Report on Ulawun (Papua New Guinea) — December 1991
Bulletin of the Global Volcanism Network, vol. 16, no. 12 (December 1991)
Managing Editor: Lindsay McClelland.
Ulawun (Papua New Guinea) Vapor emission and seismicity
Please cite this report as:
Global Volcanism Program, 1991. Report on Ulawun (Papua New Guinea). In: McClelland, L (ed.), Bulletin of the Global Volcanism Network, 16:12. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN199112-252120.
Papua New Guinea
5.05°S, 151.33°E; summit elev. 2334 m
All times are local (unless otherwise noted)
"Ulawun remained in a non-erupting state, releasing only weak to moderate white vapour. A slight increase in seismicity occurred in December after waning temporarily at the beginning of October (BGVN 16:10). Seismic activity consisted of low-frequency earthquakes, with daily counts fluctuating between 10 and 182. High-frequency volcanic earthquakes were also recorded occasionally through the month. Ground deformation continued to show no significant change."
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 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: D. Lolok and B. Talai, RVO.