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Report on Ulawun (Papua New Guinea) — 27 October-2 November 2021


Smithsonian Institution / US Geological Survey
Weekly Volcanic Activity Report, 27 October-2 November 2021
Managing Editor: Sally Sennert.

Please cite this report as:

Global Volcanism Program, 2021. Report on Ulawun (Papua New Guinea) (Sennert, S, ed.). Weekly Volcanic Activity Report, 27 October-2 November 2021. Smithsonian Institution and US Geological Survey.

Weekly Report (27 October-2 November 2021)


Papua New Guinea

5.05°S, 151.33°E; summit elev. 2334 m

All times are local (unless otherwise noted)

RVO reported increased unrest at Ulawun. Very small discrete seismic events had been recorded for the past several months by the seismometer located on the SW flank, 5 km from the summit. A small thermal anomaly was identified in satellite images at around 0500 on 3 November. At approximately 0800 RSAM values increased to 100, and by 1115, had risen to 1,400. The values fluctuated between 100 and 1,000 units at least through 1300 when the data was summarized. Tremor was detected on a seismometer at Ulamona, 11-12 km NW from the summit, during periods with higher RSAM values. Steam emissions rose from the crater.

Geological Summary. 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)