Report on Manam (Papua New Guinea) — December 1988
Scientific Event Alert Network Bulletin, vol. 13, no. 12 (December 1988)
Managing Editor: Lindsay McClelland.
Manam (Papua New Guinea) Ash and incandescent fragments; frequent B-type events
Please cite this report as:
Global Volcanism Program, 1988. Report on Manam (Papua New Guinea) (McClelland, L., ed.). Scientific Event Alert Network Bulletin, 13:12. Smithsonian Institution.
Papua New Guinea
4.08°S, 145.037°E; summit elev. 1807 m
All times are local (unless otherwise noted)
"Activity . . . remained at a low level throughout December. Both Southern and Main Craters released white vapours at weak to moderate rates. Emissions from Southern Crater were often ash-bearing and were accompanied by thick blue vapours on the 13th. Deep rumbling noises from Southern Crater were heard 1-12, 15, and 23-27 December, accompanied by weak ejections of incandescent lava fragments on the 3rd and 4th. Weak fluctuating glow from Southern Crater was observed 1-8 and 11 December. Seismicity remained at a low to moderate level with 700-1,100 B-type volcanic events recorded daily. Sub-continuous low-amplitude tremor was also recorded throughout the month. No significant tilt changes were detected."
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: H. Patia and P. Lowenstein, RVO.