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Report on Long Island (Papua New Guinea) — February 1979

Long Island

Scientific Event Alert Network Bulletin, vol. 4, no. 2 (February 1979)
Managing Editor: David Squires.

Long Island (Papua New Guinea) Fumarolic activity, but no eruption

Please cite this report as:

Global Volcanism Program, 1979. Report on Long Island (Papua New Guinea) (Squires, D., ed.). Scientific Event Alert Network Bulletin, 4:2. Smithsonian Institution. https://doi.org/10.5479/si.GVP.SEAN197902-251050

Long Island

Papua New Guinea

5.358°S, 147.12°E; summit elev. 1280 m

All times are local (unless otherwise noted)

"An aerial inspection of Long Island on 23 February confirmed that no eruption had taken place in January. Only small volumes of vapour were seen emanating from the summit craters and from a fumarole at the W shoreline. This fumarole is in a different position from the powerful one seen on 29 January."

Geological Summary. The broad profile of hexagonal-shaped Long Island is dominated by two steep-sided stratovolcanoes, Mount Reaumur in the north and Cerisy Peak in the south. Collapse of the basaltic-andesitic volcanic complex produced a large 10 x 12.5 km caldera, now filled by Lake Wisdom. Caldera formation occurred during at least three major explosive eruptions, about 16,000, 4000, and 300 years ago. The latter was one of the largest historical eruptions in Papua New Guinea and deposited andesitic tephra across the New Guinea highlands, prompting legends of a "Time of Darkness." Post-caldera eruptions have constructed a small cone, Motmot Island, in the south-central part of Lake Wisdom. Moderate explosive eruptions have occurred during the 20th century from vents at and near Motmot Island.

Information Contacts: C. McKee, RVO.