Activity at Manam's two summit craters remained low during February 2004. The summit area was cloud covered most of the month; however, when clear, both craters were observed releasing white vapor at weak to moderate rates. A single explosion occurred during the month, on 14 February at Southern Crater. A thick dark gray ash cloud and weak roaring noises accompanied the explosion. The ash cloud rose several hundred meters above the summit before drifting NW of the island, resulting in fine ashfall downwind. There was no nighttime glow observed.

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.

Information Contacts: Rabaul Volcano Observatory (RVO), P.O. Box 386, Rabaul, Papua New Guinea.