The RVO reported continuous emissions of ash clouds from Manam's Main Crater during 14-17 August. On 14 August, dense pale gray-to-brown ash clouds rose to less than 1 km above the summit (~9,200 ft a.s.l.) and drifted WNW. During 15-17 August, the emissions decreased to diffuse pale gray ash clouds and weak incandescence was observed at night.

Based on pilot reports and satellite imagery, the Darwin VAAC reported continuous emissions during 17-21 August. The plumes reached altitudes of 3.7 km (12,000 ft) a.s.l. and drifted NW.

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.

Sources: Darwin Volcanic Ash Advisory Centre (VAAC), Rabaul Volcano Observatory (RVO)