Report on Ulawun (Papua New Guinea) — June 1989
Scientific Event Alert Network Bulletin, vol. 14, no. 6 (June 1989)
Managing Editor: Lindsay McClelland.
Ulawun (Papua New Guinea) White vapor plume; seismicity decreases
Please cite this report as:
Global Volcanism Program, 1989. Report on Ulawun (Papua New Guinea). In: McClelland, L. (ed.), Scientific Event Alert Network Bulletin, 14:6. Smithsonian Institution. https://doi.org/10.5479/si.GVP.SEAN198906-252120.
Papua New Guinea
5.05°S, 151.33°E; summit elev. 2334 m
All times are local (unless otherwise noted)
"The level of activity has shown a continuous decrease since the mild phreatic unrest in March. Throughout the month, the terminal crater was releasing a plume of white vapour, while the seismicity was steadily decreasing . . . "
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: P. de Saint-Ours and B. Talai, RVO.