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 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.
Source: Rabaul Volcano Observatory (RVO)