Report on Ulawun (Papua New Guinea) — January 1983
Scientific Event Alert Network Bulletin, vol. 8, no. 1 (January 1983)
Managing Editor: Lindsay McClelland.
Ulawun (Papua New Guinea) Weak vapor emission; seismicity increases
Please cite this report as:
Global Volcanism Program, 1983. Report on Ulawun (Papua New Guinea). In: McClelland, L (ed.), Scientific Event Alert Network Bulletin, 8:1. Smithsonian Institution. http://dx.doi.org/10.5479/si.GVP.SEAN198301-252120.
Papua New Guinea
5.05°S, 151.33°E; summit elev. 2334 m
All times are local (unless otherwise noted)
"After the 24 December increase in vapour emission, Ulawun was back to a rather low level of activity. The summit crater released a low-pressure, sulfur-laden vapour plume, and daily seismicity included fewer than 1,000 B-type recorded events. In January the seismicity steadily increased again in both amplitude and frequency, to its former moderate level of 1,000-1,300 events per day."
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: P. de Saint Ours and B. Talai, RVO.