Report on Ulawun (Papua New Guinea) — February 1991
Bulletin of the Global Volcanism Network, vol. 16, no. 2 (February 1991)
Managing Editor: Lindsay McClelland.
Ulawun (Papua New Guinea) Small earthquake swarm but no change in vapor emission
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, 16:2. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN199102-252120.
Papua New Guinea
5.05°S, 151.33°E; summit elev. 2334 m
All times are local (unless otherwise noted)
"Activity at Ulawun has been at a low level since January 1990, producing small amounts of white vapour and few earthquakes. A temporary increase in seismicity was recorded between 11 and 20 February 1991. The peak was on 17 February when 295 medium-frequency volcanic earthquakes occurred. All of the events in this period were of very small magnitude. There was no change to the summit crater emissions, which continued to consist of white vapour."
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: C. McKee, RVO.