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. https://doi.org/10.5479/si.GVP.SEAN198811-252120.
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. 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: I. Itikarai and P. Lowenstein, RVO.