Report on Ulawun (Papua New Guinea) — March 1995
Bulletin of the Global Volcanism Network, vol. 20, no. 3 (March 1995)
Managing Editor: Richard Wunderman.
Ulawun (Papua New Guinea) Continued moderate vapor emissions; SO2 data from October 1994
Please cite this report as:
Global Volcanism Program, 1995. Report on Ulawun (Papua New Guinea). In: Wunderman, R. (ed.), Bulletin of the Global Volcanism Network, 20:3. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN199503-252120.
Papua New Guinea
5.05°S, 151.33°E; summit elev. 2334 m
All times are local (unless otherwise noted)
Activity on most days during January-March remained at a low level, with only moderate or moderate-strong thick white vapor emissions. Seismicity was low during the first week of January, the first three weeks of February, and the first three weeks of March; the seismograph was not operational at other times.
On 6 October 1994 the stratovolcano was visited by Chris McKee and Rod Stewart (RVO), and Stan Williams and Steve Schaefer (ASU), because of reports that the gas plume was abnormally large. Williams suggested that the plume appeared larger in volume and visible extent than during his two other visits in 1983 and 1989. Airborne COSPEC measurements made in clear atmospheric conditions showed the SO2 flux to be 1,260 ± 100 t/d. Prior measurements in 1983 and 1989 were 71 and 120 t/d, respectively.
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: B. Talai, C. McKee, and R. Stewart, RVO; S. Williams and S. Schaefer, Arizona State University.