Report on Ulawun (Papua New Guinea) — 4 May-10 May 2011
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 4 May-10 May 2011
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2011. Report on Ulawun (Papua New Guinea). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 4 May-10 May 2011. 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)
RVO reported that during 1-9 May diffuse white plumes rose from Ulawun and Real-time Seismic-Amplitude Measurement (RSAM) values ranged between 70 and 100. During 9-10 May RSAM values distinctly increased, fluctuated, and peaked at 1300 units before declining back to 100 units. During this time local residents heard booming. On 10 May grey-to-brown ash plumes were observed.
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.
Source: Rabaul Volcano Observatory (RVO)