RVO reported that during 1-12 June activity at Manam was low, characterized by white vapor emissions from Southern Crater. On 13 June diffuse gray emissions were observed, and two explosions at midnight were heard in Bogia, 25-30 km SSW of Manam on the N coast of the mainland. During 14-15 June gray-to-brown ash plumes rose 100 m above the crater and incandescent fragment ejections from the crater were observed at night. Residents on the W part of the island heard explosions on 15 June. Diffuse brown-to-black ash clouds rose 600-700 m above the crater on 17 June, and then changed to dense white clouds later that day. Strombolian activity observed at night was accompanied by roaring, rumbling, and explosion noises. Shock waves were occasionally felt. Strombolian activity increased on 18 June, generating plumes that rose 800 m above the crater. At 0635 a small-to-moderate sized pyroclastic flow traveled down the SE valley and stopped 400 m a.s.l. Ash plumes from the pyroclastic flow rose 900 m above the crater. Roaring, rumbling, and explosion noises were accompanied by occasional shock waves. Plumes drifted NW.

Main Crater emitted white vapor plumes during 1-12 June. Weak but steady incandescence emanated from the crater at night on 2 and 17 June.

Geological Summary. The 10-km-wide island of Manam, lying 13 km off the northern coast of mainland Papua New Guinea, is one of the country's most active volcanoes. Four large radial valleys extend from the unvegetated summit of the conical basaltic-andesitic stratovolcano to its lower flanks. These valleys channel lava flows and pyroclastic avalanches that have sometimes reached the coast. Five small satellitic centers are located near the island's shoreline on the northern, southern, and western sides. Two summit craters are present; both are active, although most observed eruptions have originated from the southern crater, concentrating eruptive products during much of the past century into the SE valley. Frequent eruptions, typically of mild-to-moderate scale, have been recorded since 1616. Occasional larger eruptions have produced pyroclastic flows and lava flows that reached flat-lying coastal areas and entered the sea, sometimes impacting populated areas.

Source: Rabaul Volcano Observatory (RVO)