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 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.