Report on Manam (Papua New Guinea) — September 1993
Bulletin of the Global Volcanism Network, vol. 18, no. 9 (September 1993)
Managing Editor: Edward Venzke..
Manam (Papua New Guinea) Ash emissions weak but steady; moderate eruption in early August
Please cite this report as:
Global Volcanism Program, 1993. Report on Manam (Papua New Guinea). In: Venzke, E. (ed.), Bulletin of the Global Volcanism Network, 18:9. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN199309-251020.
Papua New Guinea
4.08°S, 145.037°E; summit elev. 1807 m
All times are local (unless otherwise noted)
"Manam's activity continued at a low and steady level in August and September. Weak white vapour emissions took place at Southern Crater throughout August and September with occasional weak ash emission in September. More forceful activity occurred on 6-7 August with occasional explosions producing ash-laden clouds. Main Crater activity during August and September consisted of weak white vapour emissions. Seismicity in August included several hundred low-frequency events/day which produced sub-continuous tremor on 6, 7, 20, and 29 August. In September, Manam's seismicity was steady until about the 24th, then declined with seismic amplitudes dropping by ~50%. Tilt measurements in September . . . oscillated over a range of ~1.5 µrad, reaching maximum inflation at mid-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: C. McKee, N. Lauer, L. Sipison, B. Talai, R. Stewart, and D. Lolok, RVO.