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Report on Ulawun (Papua New Guinea) — 23 June-29 June 2010

Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 23 June-29 June 2010
Managing Editor: Sally Kuhn Sennert

Please cite this report as:

Global Volcanism Program, 2010. Report on Ulawun (Papua New Guinea). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 23 June-29 June 2010. Smithsonian Institution and US Geological Survey.

Volcano Profile |  Weekly Report (23 June-29 June 2010)


Ulawun

Papua New Guinea

5.05°S, 151.33°E; summit elev. 2334 m

All times are local (unless otherwise noted)


RVO reported that white-to-gray plumes rose from Ulawun during 23-25 June and fine ash fell on the SW and NW flanks. Low rumbling was heard and dull fluctuating incandescence was observed for a brief period of time from the SE. During 25-26 June white to gray-brown plumes rose 600 m. Seismicity, dominated by volcanic tremor, remained at a moderate level until 26 June, when Real-time Seismic-Amplitude Measurement (RSAM) values declined.

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)