Report on Manam (Papua New Guinea) — November 1997
Bulletin of the Global Volcanism Network, vol. 22, no. 11 (November 1997)
Managing Editor: Richard Wunderman.
Manam (Papua New Guinea) Moderate explosions in late November
Please cite this report as:
Global Volcanism Program, 1997. Report on Manam (Papua New Guinea) (Wunderman, R., ed.). Bulletin of the Global Volcanism Network, 22:11. Smithsonian Institution.
Papua New Guinea
4.08°S, 145.037°E; summit elev. 1807 m
All times are local (unless otherwise noted)
Moderate activity dominated during November except for the last week, when Vulcanian explosions occurred at Main Crater. The mild level of activity at Main Crater that began in late August continued until mid- November. Beginning on 23 November, the crater released thicker white and gray emissions. Moderate Vulcanian explosions (~700 m above the crater) started on 27 November and produced fine ashfalls. South Crater noiselessly and gently released thin to thick white vapor; a weak steady glow was visible on most nights during November.
Instrumental observation revealed no significant change in seismicity (~1,200 to 1,400 low-frequency events/day of small amplitude). Steady radial inflation of 1 µrad was detected at the Tabele observatory (4 km SW).
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: Patrice de Saint-Ours, RVO.