Report on Ulawun (Papua New Guinea) — November 1988

Scientific Event Alert Network Bulletin, vol. 13, no. 11 (November 1988)
Managing Editor: Lindsay McClelland

Ulawun (Papua New Guinea) Vapor emission intensifies; tremor

Please cite this report as:

Global Volcanism Program, 1988. Report on Ulawun (Papua New Guinea). In: McClelland, L (ed.), Scientific Event Alert Network Bulletin, 13:11. Smithsonian Institution. http://dx.doi.org/10.5479/si.GVP.SEAN198811-252120.

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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)


"Ulawun's summit crater was covered by clouds during most of November. When visible, weak-moderate white vapour emissions were observed. Vapour emission intensified during the last week of the month. November's recorded seismicity was mainly characterized by an average of 9 bands of low-amplitude, high-frequency harmonic tremor, each lasting 1-2 hours. The number and size of accompanying B-type events also increased with a maximum of 1,055 recorded on the 19th.

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: I. Itikarai and P. Lowenstein, RVO.