RVO reported low-to-moderate activity from Manam's Southern Crater during 1-15 June. Emissions consisted of gray and sometimes black ash clouds that rose from the crater on most days. Plumes drifted SE on 2 June and NW during 6-15 June. Ash fell in areas downwind between Yassa (WSW) and Baliau (NNW), and Warisi (ESE). Incandescent material was ejected from the crater, and roaring and rumbling noises were noted. Pyroclastic flows on 16 June (at 0700, 0720, 0722, and 0729) channeled into the SE valley. The last pyroclastic flow was perhaps the largest as it reached the lowest elevation, 300-400 m above sea level, but was far from populated areas. Ash plumes from the pyroclastic flows drifted WSW and WNW; ash fell in Bogia (22 km SSW, on the mainland). Emissions from Main Crater were milder and mostly characterized by white and bluish plumes. Light gray plumes were noted during 2 and 8-9 June. Fluctuating incandescence was intermittently observed and ash fell in the NW part of the island.

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)