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) (McClelland, L., ed.). Scientific Event Alert Network Bulletin, 8:1. Smithsonian Institution. https://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 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: P. de Saint Ours and B. Talai, RVO.