Report on Ulawun (Papua New Guinea) — 10 July-16 July 2013

Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 10 July-16 July 2013
Managing Editor: Sally Kuhn Sennert

Please cite this report as:

Global Volcanism Program, 2013. Report on Ulawun (Papua New Guinea). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 10 July-16 July 2013. Smithsonian Institution and US Geological Survey.

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Ulawun

Papua New Guinea

5.05°S, 151.33°E; summit elev. 2334 m

All times are local (unless otherwise noted)


RVO reported that activity at Ulawun was low during 1-14 July. Emissions from the summit crater consisted of white vapor during 1-7 July, and then changed to occasionally sub-continuous, light gray ash clouds during 8 and 11-14 July. Ash clouds changed to gray-brown on 14 July.

Seismic activity was low from 1 July through the early part of 13 July. RSAM increased from about 0700 on 14 July onwards with the emergence of continuous volcanic tremors until it reached a peak of 700 just after 0300 on 15 July. RVO noted that the last significant volcanic tremors at Ulawun were recorded in May and June 2012.

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. Ulawun 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 of the 2334-m-high Ulawun volcano is unvegetated. A prominent E-W-trending escarpment on the south may be the result of large-scale slumping. Satellitic cones occupy the NW and eastern flanks. A steep-walled valley cuts the NW side of Ulawun volcano, 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)