Report on Ulawun (Papua New Guinea) — January 1990
Bulletin of the Global Volcanism Network, vol. 15, no. 1 (January 1990)
Managing Editor: Lindsay McClelland.
Ulawun (Papua New Guinea) Weak vapor emission; 10-hour seismic swarm follows M 4.2 earthquake 25 km away
Please cite this report as:
Global Volcanism Program, 1990. Report on Ulawun (Papua New Guinea) (McClelland, L., ed.). Bulletin of the Global Volcanism Network, 15:1. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN199001-252120.
Papua New Guinea
5.05°S, 151.33°E; summit elev. 2334 m
All times are local (unless otherwise noted)
"Activity was at a low level throughout January, as it has been since July 1989. The summit crater emitted white vapour in weak to moderate amounts. The seismicity was also at a very low level, with only a few volcanic (B-type) events of very small amplitude/day. On the 4th, however, an earthquake (ML 4.2) originating 25 km away provoked the onset of a 10-hour swarm of small B-type events (~150) that ended abruptly after a string of a dozen larger events."
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. de Saint-Ours, RVO.