RVO reported that during 16-19 November white and blue plumes rose from Manam's Southern Crater. During 18-30 November crater incandescence and ejected incandescent tephra were observed on most nights, and a small volume of lava effused from a vent in the SE valley. During 20-30 November occasional dark gray ash plumes rose 500 m above the crater and produced ashfall in the NW and SE parts of the island. A small pyroclastic flow traveled down the SW valley on 21 November, and during 21-22 November roaring and rumbling was heard. White vapor plumes rose from Main Crater during the reporting period.

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)