At Manam's Main Crater, mild activity prevailed during June. In the first few days of the month emissions consisted of occasional small-moderate ash clouds to several hundred meters above the summit and very fine ashfall in the NW part of the island. Weak white vapor came from the volcano during 5-19 June. On the 19th viewers began seeing occasional small to moderate ash clouds; these continued until the 22nd. During this time fine ash again fell on the NW part of the island. During 23-30 June Main Crater chiefly emitted thin vapor. Throughout June, audible noises and summit glow remained absent.

At Southern Crater during June there were mainly weak emissions of thin white vapor. On the 28th, however, occasional white-gray ash clouds were observed.

Seismic activity was low. The daily number of low-frequency events was 140-1,600 per day. The lower daily totals took place during a period of very low summit activity (8-17 June). Data taken by the water-tube tiltmeter lacked clear 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: Ben Talai, RVO.