Report on Manam (Papua New Guinea) — July 1998
Bulletin of the Global Volcanism Network, vol. 23, no. 7 (July 1998)
Managing Editor: Richard Wunderman.
Manam (Papua New Guinea) Mild activity; a few weak ash emissions in June
Please cite this report as:
Global Volcanism Program, 1998. Report on Manam (Papua New Guinea). In: Wunderman, R. (ed.), Bulletin of the Global Volcanism Network, 23:7. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN199807-251020.
Papua New Guinea
4.08°S, 145.037°E; summit elev. 1807 m
All times are local (unless otherwise noted)
Mild activity prevailed at Manam in June. Both Main and South craters continued to emit weak-to-moderately thick white vapor throughout the month. However, Southern Crater's emission was briefly punctuated by a weak projection of ash at 1900 on 26 June that rose 600 m above the summit. Main Crater also showed glimpses of increased activity with weak emissions of ash on 29 and 30 June. No glow was visible at night from either crater.
Seismicity remained low: 820-1,400 daily low-frequency events of very low amplitudes. The water-tube tiltmeters at Tabele Observatory (4 km SW of the summit) showed an inflation of 1 µrad during the month.
Geologic Background. 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 1807-m-high basaltic-andesitic stratovolcano to its lower flanks. These "avalanche 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 historical eruptions have originated from the southern crater, concentrating eruptive products during much of the past century into the SE valley. Frequent historical 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.