RVO reported that increased seismic activity at Ulawun began on 7 June. During 18 June-2 July, mostly moderate-to-strong emissions of white vapor produced plumes that rose from Ulawun and seismometers recorded high-frequency earthquakes. On 22 June, noises heard in villages to the NE accompanied some of the earthquakes. On 28 June, an Intensity II earthquake was felt in areas nearby and accompanied by a booming noise. A team of officers from RVO and West New Britain Provincial Disaster Office informed communities on the activity status of Ulawun. On 30 June, RVO reported that the level of Alert at Ulawun was at "Stage 2", or that there was an increase in seismic activity above background level. During 1-2 July, roaring and jet noises were reported by people to the NE.

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)