"Visible activity intensified somewhat in April. On most days when the summit was not obscured, moderate volumes of variously white, and light to dark brown or grey emissions were seen rising above Southern crater. Occasional rumbling, roaring, and booming noises from the summit were heard at Tabele Observatory (about 4 km away). A weak glow above Southern crater was seen on 13 and 16 April, and ejections of incandescent lava fragments from there were seen on 28 and 29 April. Main crater was usually obscured, but thick white emissions were noted on 7 and 28 April. The intensity of background volcano-seismicity remained steady. A preliminary analysis indicates that only one A-type volcanic earthquake occurred in April. Tilt measurements were steady."

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: C. McKee, RVO.