RVO reported that Strombolian activity at Manam’s Southern Crater during 13-14 and 18 May generated lava flows that descended the SW valley. Lava flows traveled to 180-220 m elevation during 13-14 May but were significantly small on 18 May. Activity was low on other days during 13-26 May; ash plumes rose from the crater during 15-18 May. Conditions were quiet at Main Crater. RVO recommended that the Alert Level be lowered to Stage 1.

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)