"Activity . . . remained at a low inter-eruptive level throughout March. Both Southern and Main Craters released white vapours at weak to moderate rates. Wisps of blue vapour were also released by Crater 2 on 6-9 and 22-27 March. Weak rumbling noises were heard intermittently although no night glow, incandescent ejections, or Vulcanian explosions were reported. Seismicity remained at a normal inter-eruptive level with a daily average of 1,100-1,400 small low-frequency events superimposed on sub-continuous tremor. Tilt measurements showed no trends."

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: P. de Saint-Ours and C. McKee, RVO.