Report on Ulawun (Papua New Guinea) — 12 October-18 October 2016
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 12 October-18 October 2016
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2016. Report on Ulawun (Papua New Guinea). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 12 October-18 October 2016. 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 September-15 October white vapor plumes with varying densities rose from Ulawun, although on 12 October pale gray ash plumes rose from the vent. A report from officers at Hargy Palm Oil dated 13 October stated that a “minor eruption” had occurred after 1800 on 12 October, and that there were a few low noises from the volcano and nighttime glow during 12-13 October. RVO noted that the seismic record did not indicate an eruption.
Seismicity was at a low to moderate level, dominated by small low-frequency volcanic earthquakes. RSAM values increased and by mid-October were at the highest values (peak of 200) so far in 2016. Based on analyses of satellite imagery, the Darwin VAAC reported that during 16-17 October ash plumes rose to an altitude of 2.7 km (9,000 ft) a.s.l. and drifted SW and W.
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.
Sources: Darwin Volcanic Ash Advisory Centre (VAAC), Rabaul Volcano Observatory (RVO)