Report on Ulawun (Papua New Guinea) — December 1988

Scientific Event Alert Network Bulletin, vol. 13, no. 12 (December 1988)
Managing Editor: Lindsay McClelland.

Ulawun (Papua New Guinea) Tremor and B-type events; vapor emission

Please cite this report as:

Global Volcanism Program, 1988. Report on Ulawun (Papua New Guinea). In: McClelland, L (ed.), Scientific Event Alert Network Bulletin, 13:12. Smithsonian Institution. http://dx.doi.org/10.5479/si.GVP.SEAN198812-252120.

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Ulawun

Papua New Guinea

5.05°S, 151.33°E; summit elev. 2334 m

All times are local (unless otherwise noted)


"During most days in December, the summit crater was covered by clouds. When the weather was clear, moderate to strong white vapour emissions were observed. Seismicity was mainly characterized by bands of low-amplitude, high-frequency, harmonic tremor. The daily average of tremor bands was 8, and the mean total duration was 15 hours/day. The tremor bands were accompanied by B-type volcanic events that increased in number and amplitude during the last week of the month."

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. Ulawun 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 of the 2334-m-high Ulawun volcano 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 eastern flanks. A steep-walled valley cuts the NW side of Ulawun volcano, 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: H. Patia and P. Lowenstein, RVO.