RVO reported that during 2-7 June occasional low roaring or rumbling noises from Ulawun were heard daily in areas on the ESE, SE, and S flanks. During 2-5 June white vapor plumes rose 800-900 m high. Very fine ash particles fell in Ulamona about 10 km NW on 3 June and some gray emissions rose from the volcano on 5 June. Emissions during 6-9 June were white and light gray, and continued to rise no higher than 900 m. Fluctuating incandescence from the crater was seen at night from the S side of the volcano. Ashfall was again reported in Ulamona on 8 June.

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)