Report on Ulawun (Papua New Guinea) — 25 April-1 May 2001
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 25 April-1 May 2001
Managing Editor: Gari Mayberry
Please cite this report as:
Global Volcanism Program, 2001. Report on Ulawun (Papua New Guinea). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 25 April-1 May 2001. Smithsonian Institution and US Geological Survey.
Papua New Guinea
5.05°S, 151.33°E; summit elev. 2334 m
All times are local (unless otherwise noted)
According to the Darwin VAAC, a pilot reported observing a "smoke" cloud produced from Ulawun at 0730 on 30 April. The cloud was at an altitude of ~9 km a.s.l. and drifting to the NW and SW. Satellite imagery indicated that the cloud may have reached ~13.7 km a.s.l. and that the eruption ceased by ~1530 on 30 April. The Rabaul Volcanological Observatory stated that Ulawun is at a high alert level and further eruptions are possible.
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.